Archive for January 2017

A car enters a level, unbanked semi-circular hairpin turn of 100 m radius at a speed of 28 m/s. The coefficient of friction between the tires and the road is m = 0.800. If the car maintains a constant speed of 28 m/s, it will

A car enters a level, unbanked semi-circular hairpin turn of 100 m radius at a speed of 28 m/s. The coefficient of friction between the tires and the road is m = 0.800. If the car maintains a constant speed of 28 m/s, it will




1) attempt to dig into the road surface.
2) tend to veer toward the center of the semicircle.
3) arrive safely at the end of the semicircle.
4) tend to veer toward the outside of the circle.
5) veer toward the center for the first quarter-circle, then veer toward the outside for the second quarter-circle.







Answer: 3

A 0.20-kg object attached to the end of a string swings in a vertical circle (radius = 80 cm). At the top of the circle the speed of the object is 4.5 m/s. What is the magnitude of the tension in the string at this position?

A 0.20-kg object attached to the end of a string swings in a vertical circle (radius = 80 cm). At the top of the circle the speed of the object is 4.5 m/s. What is the magnitude of the tension in the string at this position?



1) 7.0 N
2) 2.0 N
3) 3.1 N
4) 5.1 N
5) 6.6 N








Answer: 3

An iceboat is traveling in a circle on the ice. Halfway around the circle the sail and the steering mechanism fall off the boat. Which statement is correct?

An iceboat is traveling in a circle on the ice. Halfway around the circle the sail and the steering mechanism fall off the boat. Which statement is correct?





1) The boat will continue traveling in the circle because there is no friction.
2) The boat will continue to travel in the circle because its velocity exerts a force on it.
3) The boat will move off on a line tangent to the circle because there is no force on it.
4) The boat will move off tangent to the circle because there is a force on it perpendicular to the boat directed to the outside of the circle.
5) The boat will move off to the outside perpendicular to the tangent line since a force directed to the outside of the circle always acts on the boat.





Answer: 3


When a car goes around a circular curve on a level road,

When a car goes around a circular curve on a level road,




1) no frictional force is needed because the car simply follows the road.
2) the frictional force of the road on the car increases when the car's speed decreases.
3) the frictional force of the road on the car increases when the car's speed increases.
4) the frictional force of the road on the car increases when the car moves to the outside of the curve.
5) there is no net frictional force because the road and the car exert equal and opposite forces on each other.









Answer: 3

A hornet circles around a pop can at constant speed once per second in a path with a 12-cm diameter. We can conclude that the hornet's wings must push on the air with force components that are

A hornet circles around a pop can at constant speed once per second in a path with a 12-cm diameter. We can conclude that the hornet's wings must push on the air with force components that are



1) straight down.
2) down and inwards.
3) down and outwards.
4) down and backwards.
5) down, inwards and backwards.







Answer: 3

Two small cylindrical plastic containers with flat bottoms are placed on a turntable that has a smooth flat surface. Canister A is empty; canister B contains lead shot. Each canister is the same distance r from the center. The coefficient of static friction between the canisters and the turntable is ms. When the speed of the turntable is gradually increased,

Two small cylindrical plastic containers with flat bottoms are placed on a turntable that has a smooth flat surface. Canister A is empty; canister B contains lead shot. Each canister is the same distance r from the center. The coefficient of static friction between the canisters and the turntable is ms. When the speed of the turntable is gradually increased,



1) only the lighter container slides outward off the turntable; the heavier one stays on.
2) only the heavier container slides outward off the turntable; the lighter one stays on.
3) both containers slide off the turntable at the same turntable speed.
4) the lighter container slides inward.
5) the heavier container slides inward.






Answer: 3

A 0.50-kg mass attached to the end of a string swings in a vertical circle (radius = 2.0 m). When the mass is at the lowest point on the circle, the speed of the mass is 12 m/s. What is the magnitude of the force of the string on the mass at this position?

A 0.50-kg mass attached to the end of a string swings in a vertical circle (radius = 2.0 m). When the mass is at the lowest point on the circle, the speed of the mass is 12 m/s. What is the magnitude of the force of the string on the mass at this position?




1) 31 N
2) 36 N
3) 41 N
4) 46 N
5) 23 N








Answer: 3

For a plane to be able to fly clockwise in a horizontal circle as seen from above, in addition to exerting a force downwards on the air

For a plane to be able to fly clockwise in a horizontal circle as seen from above, in addition to exerting a force downwards on the air




1) it must be increasing its speed.
2) it must exert a force on the air that is directed to the plane's left side.
3) it must exert a force on the air that is directed to the plane's right side.
4) it does not need to exert a force: it must only move the wing flaps out.
5) it only needs to deflect the air without exerting any additional force on the air.








Answer: 2

An airplane moves 140 m/s as it travels around a vertical circular loop which has a 1.0-km radius. What is the magnitude of the resultant force on the 70-kg pilot of this plane at the bottom of this loop?

An airplane moves 140 m/s as it travels around a vertical circular loop which has a 1.0-km radius. What is the magnitude of the resultant force on the 70-kg pilot of this plane at the bottom of this loop?





1) 2.1 kN
2) 1.4 kN
3) 0.69 kN
4) 1.5 kN
5) 1.3 kN







Answer: 2

A 0.50 kg mass attached to the end of a string swings in a vertical circle (radius = 2.0 m). When the mass is at the highest point of the circle the speed of the mass is 8.0 m/s. What is the magnitude of the force of the string on the mass at this position?

A 0.50 kg mass attached to the end of a string swings in a vertical circle (radius = 2.0 m). When the mass is at the highest point of the circle the speed of the mass is 8.0 m/s. What is the magnitude of the force of the string on the mass at this position?





1) 21 N
2) 11 N
3) 16 N
4) 26 N
5) 36 N








Answer: 2

A stunt pilot weighing 0.70 kN performs a vertical circular dive of radius 0.80 km. At the bottom of the dive, the pilot has a speed of 0.20 km/s which at that instant is not changing. What force does the plane exert on the pilot?

A stunt pilot weighing 0.70 kN performs a vertical circular dive of radius 0.80 km. At the bottom of the dive, the pilot has a speed of 0.20 km/s which at that instant is not changing. What force does the plane exert on the pilot?



1) 3.6 kN up
2) 4.3 kN up
3) 2.9 kN down
4) 2.9 kN up
5) 5.8 kN down








Answer: 2

A 4.0-kg mass on the end of a string rotates in a circular motion on a horizontal frictionless table. The mass has a constant speed of 2.0 m/s and the radius of the circle is 0.80 m. What is the magnitude of the resultant force acting on the mass?

A 4.0-kg mass on the end of a string rotates in a circular motion on a horizontal frictionless table. The mass has a constant speed of 2.0 m/s and the radius of the circle is 0.80 m. What is the magnitude of the resultant force acting on the mass?



1) 39 N
2) 20 N
3) 44 N
4) 0 N
5) 30 N







Answer: 2

A split highway has a number of lanes for traffic. For traffic going in one direction, the radius for the inside of the curve is half the radius for the outside. One car, car A, travels on the inside while another car of equal mass, car B, travels at equal speed on the outside of the curve. Which statement about resultant forces on the cars is correct?

A split highway has a number of lanes for traffic. For traffic going in one direction, the radius for the inside of the curve is half the radius for the outside. One car, car A, travels on the inside while another car of equal mass, car B, travels at equal speed on the outside of the curve. Which statement about resultant forces on the cars is correct?



1) The force on A is half the force on B.
2) The force on B is half the force on A.
3) The force on A is four times the force on B.
4) The force on B is four times the force on A.
5) There is no net resultant force on either as long as they stay on the road while turning.





Answer: 2

An airplane flies in a horizontal circle of radius 500 m at a speed of 150 m/s. If the radius were changed to 1000 m, but the speed remained the same, by what factor would its centripetal acceleration change?

An airplane flies in a horizontal circle of radius 500 m at a speed of 150 m/s. If the radius were changed to 1000 m, but the speed remained the same, by what factor would its centripetal acceleration change?



1) 0.25
2) 0.50
3) 1.00
4) 2.00
5) 4.00








Answer: 2

A 50-kg child riding a Ferris wheel (radius = 10 m) travels in a vertical circle. The wheel completes one revolution every 10 s. What is the magnitude of the force on the child by the seat at the highest point on the circular path?

A 50-kg child riding a Ferris wheel (radius = 10 m) travels in a vertical circle. The wheel completes one revolution every 10 s. What is the magnitude of the force on the child by the seat at the highest point on the circular path?



1) 0.29 kN
2) 0.49 kN
3) 0.69 kN
4) 0.20 kN
5) 0.40 kN








Answer: 1

A race car traveling at 100 m/s enters an unbanked turn of 400 m radius. The coefficient of (static) friction between the tires and the track is 1.1. The track has both an inner and an outer wall. Which statement is correct?

A race car traveling at 100 m/s enters an unbanked turn of 400 m radius. The coefficient of (static) friction between the tires and the track is 1.1. The track has both an inner and an outer wall. Which statement is correct?




1) The race car will crash into the outer wall.
2) The race car will crash into the inner wall.
3) The car will stay in the center of the track.
4) The car will stay in the center of the track if the driver speeds up.
5) The car would stay in the center of the track if the radius were reduced to 200 m.







Answer: 1

A 0.50-kg mass attached to the end of a string swings in a vertical circle (radius = 2.0 m). When the string is horizontal, the speed of the mass is 8.0 m/s. What is the magnitude of the force of the string on the mass at this position?

A 0.50-kg mass attached to the end of a string swings in a vertical circle (radius = 2.0 m). When the string is horizontal, the speed of the mass is 8.0 m/s. What is the magnitude of the force of the string on the mass at this position?




1) 16 N
2) 17 N
3) 21 N
4) 11 N
5) 25 N







Answer: 1

A 30-kg child rides on a circus Ferris wheel that takes her around a vertical circular path with a radius of 20 m every 22 s. What is the magnitude of the resultant force on the child at the highest point on this trajectory?

A 30-kg child rides on a circus Ferris wheel that takes her around a vertical circular path with a radius of 20 m every 22 s. What is the magnitude of the resultant force on the child at the highest point on this trajectory?



1) 49 N
2) 0.29 kN
3) 0.34 kN
4) 0.25 kN
5) 0.76 kN







Answer: 1

A 1.6-kg ball is attached to the end of a 0.40-m string to form a pendulum. This pendulum is released from rest with the string horizontal. At the lowest point of its swing, when it is moving horizontally, the ball collides with a 0.80-kg block initially at rest on a horizontal frictionless surface. The speed of the block just after the collision is 3.0 m/s. What is the speed of the ball just after the collision?

A 1.6-kg ball is attached to the end of a 0.40-m string to form a pendulum. This pendulum is released from rest with the string horizontal. At the lowest point of its swing, when it is moving horizontally, the ball collides with a 0.80-kg block initially at rest on a horizontal frictionless surface. The speed of the block just after the collision is 3.0 m/s. What is the speed of the ball just after the collision?




1) 1.7 m/s
2) 1.1 m/s
3) 1.5 m/s
4) 1.3 m/s
5) 2.1 m/s







Answer: 4

A 5.0-kg mass with an initial velocity of 4.0 m/s, east collides with a 4.0-kg mass with an initial velocity of 3.0 m/s, west. After the collision the 5.0-kg mass has a velocity of 1.2 m/s, south. What is the magnitude of the velocity of the 4.0-kg mass after the collision?

A 5.0-kg mass with an initial velocity of 4.0 m/s, east collides with a 4.0-kg mass with an initial velocity of 3.0 m/s, west. After the collision the 5.0-kg mass has a velocity of 1.2 m/s, south. What is the magnitude of the velocity of the 4.0-kg mass after the collision?




1) 2.0 m/s
2) 1.5 m/s
3) 1.0 m/s
4) 2.5 m/s
5) 3.0 m/s






Answer: 4

Two bodies with masses m1 and m2 are both moving east with velocities of magnitudes v1 and v2, where v1 is less than v2. The magnitude of the velocity of the center of mass of this system of two bodies is

Two bodies with masses m1 and m2 are both moving east with velocities of magnitudes v1 and v2, where v1 is less than v2. The magnitude of the velocity of the center of mass of this system of two bodies is





1) less than v1.
2) equal to v1.
3) equal to the average of v1 and v2.
4) greater than v1 and less than v2.
5) greater than v2.






Answer: 4

An 80-g particle moving with an initial speed of 50 m/s in the positive x direction strikes and sticks to a 60-g particle moving 50 m/s in the positive y direction. How much kinetic energy is lost in this collision?

An 80-g particle moving with an initial speed of 50 m/s in the positive x direction strikes and sticks to a 60-g particle moving 50 m/s in the positive y direction. How much kinetic energy is lost in this collision?




1) 96 J
2) 89 J
3) 175 J
4) 86 J
5) 110 J






Answer: 4

A rocket moving in outer space maintains a constant acceleration (magnitude = 20 m/s2) while ejecting fuel at a speed of 15 km/s relative to the rocket. If the initial mass of the rocket is 3000 kg, what is the magnitude of the thrust after 800 kg of fuel have been consumed?

A rocket moving in outer space maintains a constant acceleration (magnitude = 20 m/s2) while ejecting fuel at a speed of 15 km/s relative to the rocket. If the initial mass of the rocket is 3000 kg, what is the magnitude of the thrust after 800 kg of fuel have been consumed?



1) 56 kN
2) 48 kN
3) 52 kN
4) 44 kN
5) 36 kN






Answer: 4

A 6.0-kg object moving 5.0 m/s collides with and sticks to a 2.0-kg object. After the collision the composite object is moving 2.0 m/s in a direction opposite to the initial direction of motion of the 6.0-kg object. Determine the speed of the 2.0-kg object before the collision.

A 6.0-kg object moving 5.0 m/s collides with and sticks to a 2.0-kg object. After the collision the composite object is moving 2.0 m/s in a direction opposite to the initial direction of motion of the 6.0-kg object. Determine the speed of the 2.0-kg object before the collision.



1) 15 m/s
2) 7.0 m/s
3) 8.0 m/s
4) 23 m/s
5) 11 m/s








Answer: 4

Three particles are placed in the xy plane. A 40-g particle is located at (3, 4) m, and a 50-g particle is positioned at (-2, -6) m. Where must a 20-g particle be placed so that the center of mass of this three-particle system is located at the origin?

Three particles are placed in the xy plane. A 40-g particle is located at (3, 4) m, and a 50-g particle is positioned at (-2, -6) m. Where must a 20-g particle be placed so that the center of mass of this three-particle system is located at the origin?




1) (-1, -3) m
2) (-1, 2) m
3) (-1, 12) m
4) (-1, 7) m
5) (-1, 3) m








Answer: 4

A 3.0-kg object moving in the positive x direction has a one-dimensional elastic collision with a 5.0-kg object initially at rest. After the collision the 5.0-kg object has a velocity of 6.0 m/s in the positive x direction. What was the initial speed of the 3.0 kg object?

A 3.0-kg object moving in the positive x direction has a one-dimensional elastic collision with a 5.0-kg object initially at rest. After the collision the 5.0-kg object has a velocity of 6.0 m/s in the positive x direction. What was the initial speed of the 3.0 kg object?



1) 6.0 m/s
2) 7.0 m/s
3) 4.5 m/s
4) 8.0 m/s
5) 5.5 m/s








Answer: 4

A 2.0-kg object moving with a velocity of 5.0 m/s in the positive x direction strikes and sticks to a 3.0-kg object moving with a speed of 2.0 m/s in the same direction. How much kinetic energy is lost in this collision?

A 2.0-kg object moving with a velocity of 5.0 m/s in the positive x direction strikes and sticks to a 3.0-kg object moving with a speed of 2.0 m/s in the same direction. How much kinetic energy is lost in this collision?




1) 2.4 J
2) 9.6 J
3) 5.4 J
4) 0.6 J
5) 6.0 J







Answer: 3

A 4.0-kg mass has a velocity of 4.0 m/s, east when it explodes into two 2.0-kg masses. After the explosion one of the masses has a velocity of 3.0 m/s at an angle of 60° north of east. What is the magnitude of the velocity of the other mass after the explosion?

A 4.0-kg mass has a velocity of 4.0 m/s, east when it explodes into two 2.0-kg masses. After the explosion one of the masses has a velocity of 3.0 m/s at an angle of 60° north of east. What is the magnitude of the velocity of the other mass after the explosion?




1) 7.9 m/s
2) 8.9 m/s
3) 7.0 m/s
4) 6.1 m/s
5) 6.7 m/s







Answer: 3

A 2.0-kg object moving 3.0 m/s strikes a 1.0-kg object initially at rest. Immediately after the collision, the 2.0-kg object has a velocity of 1.5 m/s directed 30° from its initial direction of motion. What is the y-component of the velocity of the 1.0-kg object just after the collision?

A 2.0-kg object moving 3.0 m/s strikes a 1.0-kg object initially at rest. Immediately after the collision, the 2.0-kg object has a velocity of 1.5 m/s directed 30° from its initial direction of motion. What is the y-component of the velocity of the 1.0-kg object just after the collision?




1) -3.7 m/s
2) -3.4 m/s
3) -1.5 m/s
4) -2.4 m/s
5) -4.1 m/s







Answer: 3

At an instant when a particle of mass 50 g has an acceleration of 80 m/s2 in the positive x direction, a 75-g particle has an acceleration of 40 m/s2 in the positive y direction. What is the magnitude of the acceleration of the center of mass of this two-particle system at this instant?

At an instant when a particle of mass 50 g has an acceleration of 80 m/s2 in the positive x direction, a 75-g particle has an acceleration of 40 m/s2 in the positive y direction. What is the magnitude of the acceleration of the center of mass of this two-particle system at this instant?



1) 60 m/s2
2) 56 m/s2
3) 40 m/s2
4) 50 m/s2
5) 46 m/s2






Answer: 3

A 2000-kg truck traveling at a speed of 6.0 m/s makes a 90° turn in a time of 4.0 s and emerges from this turn with a speed of 4.0 m/s. What is the magnitude of the average resultant force on the truck during this turn?

A 2000-kg truck traveling at a speed of 6.0 m/s makes a 90° turn in a time of 4.0 s and emerges from this turn with a speed of 4.0 m/s. What is the magnitude of the average resultant force on the truck during this turn?




1) 4.0 kN
2) 5.0 kN
3) 3.6 kN
4) 6.4 kN
5) 0.67 kN







Answer: 3

A 6.0-kg object, initially at rest in free space, "explodes" into three segments of equal mass. Two of these segments are observed to be moving with equal speeds of 20 m/s with an angle of 60° between their directions of motion. How much kinetic energy is released in this explosion?

A 6.0-kg object, initially at rest in free space, "explodes" into three segments of equal mass. Two of these segments are observed to be moving with equal speeds of 20 m/s with an angle of 60° between their directions of motion. How much kinetic energy is released in this explosion?




1) 2.4 kJ
2) 2.9 kJ
3) 2.0 kJ
4) 3.4 kJ
5) 1.2 kJ






Answer: 3

A pendulum consists of a 2.0-kg block hanging on a 1.5-m length string. A 10-g bullet moving with a horizontal velocity of 900 m/s strikes, passes through, and emerges from the block (initially at rest) with a horizontal velocity of 300 m/s. To what maximum height above its initial position will the block swing?

A pendulum consists of a 2.0-kg block hanging on a 1.5-m length string. A 10-g bullet moving with a horizontal velocity of 900 m/s strikes, passes through, and emerges from the block (initially at rest) with a horizontal velocity of 300 m/s. To what maximum height above its initial position will the block swing?



1) 32 cm
2) 38 cm
3) 46 cm
4) 27 cm
5) 9 cm







Answer: 3

A 1.0-kg object moving 9.0 m/s collides with a 2.0-kg object moving 6.0 m/s in a direction that is perpendicular to the initial direction of motion of the 1.0-kg object. The two masses remain together after the collision, and this composite object then collides with and sticks to a 3.0-kg object. After these collisions, the final composite (6.0-kg) object remains at rest. What was the speed of the 3.0-kg object before the collisions?

A 1.0-kg object moving 9.0 m/s collides with a 2.0-kg object moving 6.0 m/s in a direction that is perpendicular to the initial direction of motion of the 1.0-kg object. The two masses remain together after the collision, and this composite object then collides with and sticks to a 3.0-kg object. After these collisions, the final composite (6.0-kg) object remains at rest. What was the speed of the 3.0-kg object before the collisions?



1) 15 m/s
2) 10 m/s
3) 5.0 m/s
4) 20 m/s
5) 25 m/s









Answer: 3

An 8.0-kg object moving 4.0 m/s in the positive x direction has a one-dimensional collision with a 2.0-kg object moving 3.0 m/s in the opposite direction. The final velocity of the 8.0-kg object is 2.0 m/s in the positive x direction. What is the total kinetic energy of the two-mass system after the collision?

An 8.0-kg object moving 4.0 m/s in the positive x direction has a one-dimensional collision with a 2.0-kg object moving 3.0 m/s in the opposite direction. The final velocity of the 8.0-kg object is 2.0 m/s in the positive x direction. What is the total kinetic energy of the two-mass system after the collision?



1) 32 J
2) 52 J
3) 41 J
4) 25 J
5) 29 J







Answer: 3

A 1.2-kg object moving with a speed of 8.0 m/s collides perpendicularly with a wall and emerges with a speed of 6.0 m/s in the opposite direction. If the object is in contact with the wall for 2.0 ms, what is the magnitude of the average force on the object by the wall?

A 1.2-kg object moving with a speed of 8.0 m/s collides perpendicularly with a wall and emerges with a speed of 6.0 m/s in the opposite direction. If the object is in contact with the wall for 2.0 ms, what is the magnitude of the average force on the object by the wall?



1) 9.8 kN
2) 8.4 kN
3) 7.7 kN
4) 9.1 kN
5) 1.2 kN






Answer: 2

A 3.0-kg mass moving in the positive x direction with a speed of 10 m/s collides with a 6.0-kg mass initially at rest. After the collision, the speed of the 3.0-kg mass is 8.0 m/s, and its velocity vector makes an angle of 35° with the positive x axis. What is the magnitude of the velocity of the 6.0-kg mass after the collision?

A 3.0-kg mass moving in the positive x direction with a speed of 10 m/s collides with a 6.0-kg mass initially at rest. After the collision, the speed of the 3.0-kg mass is 8.0 m/s, and its velocity vector makes an angle of 35° with the positive x axis. What is the magnitude of the velocity of the 6.0-kg mass after the collision?




1) 2.2 m/s
2) 2.9 m/s
3) 4.2 m/s
4) 3.5 m/s
5) 4.7 m/s






Answer: 2

A 3.0-kg object moving 8.0 m/s in the positive x direction has a one-dimensional elastic collision with an object (mass = M) initially at rest. After the collision the object of unknown mass has a velocity of 6.0 m/s in the positive x direction. What is M?

A 3.0-kg object moving 8.0 m/s in the positive x direction has a one-dimensional elastic collision with an object (mass = M) initially at rest. After the collision the object of unknown mass has a velocity of 6.0 m/s in the positive x direction. What is M?



1) 7.5 kg
2) 5.0 kg
3) 6.0 kg
4) 4.2 kg
5) 8.0 kg







Answer: 2

A 12-g bullet moving horizontally strikes and remains in a 3.0-kg block initially at rest on the edge of a table. The block, which is initially 80 cm above the floor, strikes the floor a horizontal distance of 120 cm from its initial position. What was the initial speed of the bullet?

A 12-g bullet moving horizontally strikes and remains in a 3.0-kg block initially at rest on the edge of a table. The block, which is initially 80 cm above the floor, strikes the floor a horizontal distance of 120 cm from its initial position. What was the initial speed of the bullet?



1) 0.68 km/s
2) 0.75 km/s
3) 0.81 km/s
4) 0.87 km/s
5) 0.41 km/s







Answer: 2

A 12-g bullet moving horizontally strikes and remains in a 3.0-kg block initially at rest on the edge of a table. The block, which is initially 80 cm above the floor, strikes the floor a horizontal distance of 120 cm from its initial position. What was the initial speed of the bullet?

A 12-g bullet moving horizontally strikes and remains in a 3.0-kg block initially at rest on the edge of a table. The block, which is initially 80 cm above the floor, strikes the floor a horizontal distance of 120 cm from its initial position. What was the initial speed of the bullet?



1) 0.68 km/s
2) 0.75 km/s
3) 0.81 km/s
4) 0.87 km/s
5) 0.41 km/s







Answer: 2

A 4.0-kg mass, initially at rest on a horizontal frictionless surface, is struck by a 2.0-kg mass moving along the x axis with a speed of 8.0 m/s. After the collision, the 2.0-kg mass has a speed of 4.0 m/s at an angle of 37° from the positive x axis. What is the speed of the 4.0-kg mass after the collision?

A 4.0-kg mass, initially at rest on a horizontal frictionless surface, is struck by a 2.0-kg mass moving along the x axis with a speed of 8.0 m/s. After the collision, the 2.0-kg mass has a speed of 4.0 m/s at an angle of 37° from the positive x axis. What is the speed of the 4.0-kg mass after the collision?



1) 2.0 m/s
2) 2.7 m/s
3) 4.9 m/s
4) 2.4 m/s
5) 3.6 m/s






Answer: 2

A 5.0-g particle moving 60 m/s collides with a 2.0-g particle initially at rest. After the collision each of the particles has a velocity that is directed 30° from the original direction of motion of the 5.0-g particle. What is the speed of the 2.0-g particle after the collision?

A 5.0-g particle moving 60 m/s collides with a 2.0-g particle initially at rest. After the collision each of the particles has a velocity that is directed 30° from the original direction of motion of the 5.0-g particle. What is the speed of the 2.0-g particle after the collision?



1) 72 m/s
2) 87 m/s
3) 79 m/s
4) 94 m/s
5) 67 m/s







Answer: 2

A 1.5-kg playground ball is moving with a velocity of 3.0 m/s directed 30° below the horizontal just before it strikes a horizontal surface. The ball leaves this surface 0.50 s later with a velocity of 2.0 m/s directed 60° above the horizontal. What is the magnitude of the average resultant force on the ball?

A 1.5-kg playground ball is moving with a velocity of 3.0 m/s directed 30° below the horizontal just before it strikes a horizontal surface. The ball leaves this surface 0.50 s later with a velocity of 2.0 m/s directed 60° above the horizontal. What is the magnitude of the average resultant force on the ball?



1) 14 N
2) 11 N
3) 18 N
4) 22 N
5) 3.0 N







Answer: 2

A 2.0-kg object moving 3.0 m/s strikes a 1.0-kg object initially at rest. Immediately after the collision, the 2.0-kg object has a velocity of 1.5 m/s directed 30° from its initial direction of motion. What is the x-component of the velocity of the 1.0-kg object just after the collision?

A 2.0-kg object moving 3.0 m/s strikes a 1.0-kg object initially at rest. Immediately after the collision, the 2.0-kg object has a velocity of 1.5 m/s directed 30° from its initial direction of motion. What is the x-component of the velocity of the 1.0-kg object just after the collision?



1) 3.7 m/s
2) 3.4 m/s
3) 1.5 m/s
4) 2.4 m/s
5) 4.1 m/s








Answer: 2

The speed of a 2.0-kg object changes from 30 m/s to 40 m/s during a 5.0-s time interval. During this same time interval, the velocity of the object changes its direction by 90°. What is the magnitude of the average total force acting on the object during this time interval?

The speed of a 2.0-kg object changes from 30 m/s to 40 m/s during a 5.0-s time interval. During this same time interval, the velocity of the object changes its direction by 90°. What is the magnitude of the average total force acting on the object during this time interval?



1) 30 N
2) 20 N
3) 40 N
4) 50 N
5) 6.0 N








Answer: 2

The speed of a 2.0-kg object changes from 30 m/s to 40 m/s during a 5.0-s time interval. During this same time interval, the velocity of the object changes its direction by 90°. What is the magnitude of the average total force acting on the object during this time interval?

The speed of a 2.0-kg object changes from 30 m/s to 40 m/s during a 5.0-s time interval. During this same time interval, the velocity of the object changes its direction by 90°. What is the magnitude of the average total force acting on the object during this time interval?



1) 30 N
2) 20 N
3) 40 N
4) 50 N
5) 6.0 N








Answer: 2

A 4.0-kg particle is moving horizontally with a speed of 5.0 m/s when it strikes a vertical wall. The particle rebounds with a speed of 3.0 m/s. What is the magnitude of the impulse delivered to the particle?

A 4.0-kg particle is moving horizontally with a speed of 5.0 m/s when it strikes a vertical wall. The particle rebounds with a speed of 3.0 m/s. What is the magnitude of the impulse delivered to the particle?



1) 24 N × s
2) 32 N × s
3) 40 N × s
4) 30 N × s
5) 8.0 N × s








Answer: 2

A 10-g bullet moving horizontally with a speed of 1.8 km/s strikes and passes through a 5.0-kg block initially at rest on a horizontal frictionless surface. The bullet emerges from the block with a speed of 1.0 km/s. What is the kinetic energy of the block immediately after the bullet emerges?

A 10-g bullet moving horizontally with a speed of 1.8 km/s strikes and passes through a 5.0-kg block initially at rest on a horizontal frictionless surface. The bullet emerges from the block with a speed of 1.0 km/s. What is the kinetic energy of the block immediately after the bullet emerges?



1) 8.0 J
2) 6.4 J
3) 5.3 J
4) 9.4 J
5) 10 J







Answer: 2

A 1.0-kg ball is attached to the end of a 2.5-m string to form a pendulum. This pendulum is released from rest with the string horizontal. At the lowest point in its swing when it is moving horizontally, the ball collides elastically with a 2.0-kg block initially at rest on a horizontal frictionless surface. What is the speed of the block just after the collision

A 1.0-kg ball is attached to the end of a 2.5-m string to form a pendulum. This pendulum is released from rest with the string horizontal. At the lowest point in its swing when it is moving horizontally, the ball collides elastically with a 2.0-kg block initially at rest on a horizontal frictionless surface. What is the speed of the block just after the collision?



1) 2.3 m/s
2) 4.7 m/s
3) 3.5 m/s
4) 3.0 m/s
5) 7.0 m/s








Answer: 2

A 1.0-kg ball is attached to the end of a 2.5-m string to form a pendulum. This pendulum is released from rest with the string horizontal. At the lowest point in its swing when it is moving horizontally, the ball collides elastically with a 2.0-kg block initially at rest on a horizontal frictionless surface. What is the speed of the block just after the collision?

A 1.0-kg ball is attached to the end of a 2.5-m string to form a pendulum. This pendulum is released from rest with the string horizontal. At the lowest point in its swing when it is moving horizontally, the ball collides elastically with a 2.0-kg block initially at rest on a horizontal frictionless surface. What is the speed of the block just after the collision?






1) 2.3 m/s
2) 4.7 m/s
3) 3.5 m/s
4) 3.0 m/s
5) 7.0 m/s






Answer: 2
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