Deck 7: Linear Momentum

Question 1

A 4.00 kg ball is traveling at 5.00 m/s and strikes a wall.The 4.00 kg ball bounces off the wall with a velocity of 4.0 m/s.The change in momentum of the ball is

A) 8.0 kg m/s.
B) 13 kg m/s.
C) 26 kg m/s.
D) 30 kg m/s.
E) 36 kg m/s.

Answer 1

36 kg m/s.

Question 2

A rifle fires a bullet.Immediately after the bullet is fired,which of the following is NOT true?

A) the rifle and the bullet have the same magnitude of momentum
B) the force on the rifle due to the bullet and the force on the bullet due to the rifle have the same magnitude
C) the impulse on the rifle due to the bullet and the impulse on the bullet due to the rifle have the same magnitude
D) the rifle and the bullet do not have the same kinetic energy
E) the rifle and the bullet have the same kinetic energy

Answer 2

the rifle and the bullet have the same kinetic energy

Question 3

A 1200 kg car is traveling at 3.00 m/s and strikes a wall.The 1200 kg car bounces off the wall with a velocity of 4.00 m/s.If the contact with the wall by the car lasts for 0.10 seconds,then the average force on the car is

A) 46,000 N.
B) 55,000 N.
C) 63,000 N.
D) 75,000 N.
E) 84,000 N.

Answer 3

84,000 N.

Question 4

If the momentum of a ball is doubled,then the kinetic energy is

A) 0.5 times larger.
B) 2 times larger.
C) 3 times larger.
D) 4 times larger.
E) 5 times larger.

Question 5

If the kinetic energy of a ball is doubled,then the momentum is

A) 0.50 times larger.
B) 0.71 times larger.
C) 1.00 times larger.
D) 1.41 times larger.
E) 1.50 times larger.

Question 6

A 1200 kg car is traveling at 4.00 m/s and strikes a wall.The 1200 kg car bounces off the wall with a velocity of 4.00 m/s.If the contact with the wall by the car lasts for 0.100 seconds,then the impulse on the car is

A) 12,400 kg m/s.
B) 10,200 kg m/s.
C) 9,600 kg m/s.
D) 8,400 kg m/s.
E) 2,900 kg m/s.

Question 7

A 5.00 kg ball is traveling at 4.0 m/s and strikes a wall.The ball bounces off the wall with a velocity of 4.0 m/s in the opposite direction.If the contact with the wall by the ball lasts for 0.10 seconds,then the magnitude of the impulse on the ball is

A) 24 kg m/s.
B) 30 kg m/s.
C) 36 kg m/s.
D) 40 kg m/s.
E) 50 kg m/s.

Question 8

A rocket with a mass of 500 grams is launched straight up.It achieves a velocity of 20.0 m/s in 2.00 seconds.The average thrust force of the engines on the rocket is

A) 7.50 N.
B) 9.90 N.
C) 12.0 N.
D) 13.5 N.
E) 20.0 N

Question 9

Two objects of equal mass hit a wall with the same velocity.They both rebound with the same velocity.Both objects experience the same momentum change but one experiences twice the force as the other.Which of the following statements is true?

A) the contact time between the object and the wall of one is twice the contact time of the other
B) the contact time between the object and the wall of one is equal to the contact time of the other
C) the contact time between the object and the wall of one is one-half the contact time of the other
D) the change in the kinetic energy is the same for the two objects
E) the contact time between the object and the wall of one is 1/3 the contact time of the other

Question 10

A 3.000 kg ball is pitched with a kinetic energy of 20.00 Joules.Then the momentum of the ball is

A) 7.500 kg m/s.
B) 8.350 kg m/s.
C) 9.450 kg m/s.
D) 10.95 kg m/s.
E) 12.50 kg m/s.

Question 11

A 30.00 kg mass falls from a height of 4.000 m.The momentum of the mass just before it hits the ground is

A) 144.2 kg m/s.
B) 187.8 kg m/s.
C) 320.0 kg m/s.
D) 442.4 kg m/s.
E) 502.1 kg m/s.

Question 12

A rocket with a mass of 750 grams is launched straight up.It achieves a velocity of 25.00 m/s in 2.00 seconds.The average net force on the rocket is

A) 16.7 N.
B) 24.5 N.
C) 33.1 N.
D) 41.7 N.
E) 52.8 N.

Question 13

A 2.0 kg ball is moving at 4.0 m/s WEST.The momentum of the ball is

A) 4.00 kg m/s WEST.
B) 6.00 kg m/s WEST.
C) 8.0 kg m/s WEST.
D) 10 kg m/s WEST.
E) 12 kg m/s WEST.

Question 14

A 140 gm baseball with a velocity of 25.0 m/s is hit by a baseball bat and leaves at 30.0 m/s in the opposite direction.If the ball was in contact with the bat for 12.0 ms,what is the average force on the ball?

A) 750 N
B) 642 N
C) 550 N
D) 482 N
E) 366 N

Question 15

A 1,800 kg car is traveling at 20.0 m/s NORTHEAST.The momentum of the car is

A) 18,000 kg m/s NORTHEAST.
B) 20,000 kg m/s NORTHEAST.
C) 28,000 kg m/s NORTHEAST.
D) 32,000 kg m/s NORTHEAST.
E) 36,000 kg m/s NORTHEAST.

Question 16

A machine gun fires 60.0 gram bullets at 6 bullets a second.If the velocity of the bullets is 600 m/s,then the average force on the machine gun is

A) 67.0 N.
B) 75.0 N.
C) 94.0 N.
D) 109 N.
E) 216 N.

Question 17

The units of momentum are

A) ML/T.
B) M/T.
C) L/T².
D) ML/T².
E) ML²/T².

Question 18

A 4.00 kg ball is traveling at 3.00 m/s and strikes a wall.The 4.00 kg ball bounces off the wall with a velocity of 4.0 m/s.If the contact with the wall by the ball lasts for 0.10 seconds,then the average force on the ball is

A) 230 N.
B) 280 N.
C) 320 N.
D) 360 N.
E) 400 N.

Question 19

A water hose has a flow rate of 3.0 kg/s of water.If the velocity of the water as it leaves the hose is 5.0 m/s,then the force to hold the hose is

A) 15 N.
B) 26 N.
C) 30 N.
D) 45 N.
E) 57 N.

Question 20

An 1800 kg car traveling at 35.0 m/s strikes a wall.If the car comes to rest in 0.500 seconds,then the average force of the wall on the car is

A) 0.330 $\times$ 10⁵ N.
B) 0.640 $\times$ 10⁵ N.
C) 1.26 $\times$ 10⁵ N.
D) 2.77 $\times$ 10⁵ N.
E) 3.33 $\times$ 10⁵ N.

Question 21

An astronaut in a space suit is motionless in outer space.The propulsion unit strapped to her back ejects some gas with a velocity of 50 m/s.The astronaut recoils with a velocity of 1.0 m/s.If the mass of the astronaut and space suit after the gas is ejected is 120 kg,the mass of the gas ejected is

A) 1.0 kg.
B) 1.9 kg.
C) 2.4 kg.
D) 3.00 kg.
E) 3.6 kg.

Question 22

A 4.00 kg ball is moving at 2.00 m/s to the SOUTH and a 6.00 kg ball is moving at 2.00 m/s to the NORTHWEST.The total momentum of the system is

A) 15.8 kg m/s at an angle of 3.27 degrees NORTH of WEST.
B) 8.5 kg m/s at an angle of 3.27 degrees NORTH of WEST.
C) 15.8 kg m/s at an angle of 17.2 degrees NORTH of WEST.
D) 8.5 kg m/s at an angle of 17.2 degrees NORTH of WEST.
E) 20.1 kg m/s at an angle of 27.5 degrees NORTH of WEST.

Question 23

A 120 kg mass is blown apart into an 80 kg piece and a 40 kg piece.After the blast,the two masses are moving apart with a relative velocity of 60 m/s.The total kinetic energy after the explosion is

A) 21 kJ.
B) 35 kJ.
C) 48 kJ.
D) 56 kJ.
E) 82 kJ.

Question 24

A 100 kg mass is blown apart into a 90.0 kg piece and a 10.0 kg piece.After the blast,the two masses are moving apart with a relative velocity of 100 m/s.The velocity of the 10.0 kg mass after the explosion is 90.0 m/s.The total kinetic energy of the two masses after the explosion is

A) 63,200 J.
B) 45,000 J.
C) 30,400 J.
D) 23,400 J.
E) 4,500 J.

Question 25

A 4.00 kg ball is moving at 3.00 m/s to the NORTH and a 5.00 kg ball is moving at 2.00 m/s to the NORTHWEST.The total momentum of the system is

A) 20.3 kg m/s at an angle of 89.7 degrees NORTH of EAST.
B) 20.3 kg m/s at an angle of 24.6 degrees SOUTH of EAST.
C) 26.1 kg m/s at an angle of 24.6 degrees NORTH of EAST.
D) 26.1 kg m/s at an angle of 89.7 degrees SOUTH of EAST.
E) 43.00 kg m/s at an angle of 45.0 degrees NORTH of EAST.

Question 26

A 3.0 kg object is moving to the right at 4.0 m/s.It collides in a perfectly inelastic collision with a 6.0 kg object moving to the left at 2.0 m/s.What is the total kinetic energy after the collision?

A) 62 J
B) 25 J
C) 12 J
D) 0.0 J

Question 27

A 90.0 kg person is sitting in a boat at rest with a mass of 100 kg.In the boat is a stone with a mass of 5.00 kg.The person throws the stone at 4.00 m/s horizontally in the NORTH direction.The kinetic energy of the boat and person after the throwing of the stone is

A) 5.20 J.
B) 40.0 J.
C) 1.05 J.
D) 2.75 J.

Question 28

Two ice skaters are at rest and facing each other.One skater weighs 140 lbs and the other skater weighs 180 lbs.The skaters "push off" of each other.The 140 lb skater is moving at 5.00 m/s to the EAST.What is the velocity of the 180 lb skater?

A) 6.50 m/s EAST
B) 6.50 m/s WEST
C) 3.89 m/s EAST
D) 3.89 m/s WEST
E) 1.55 m/s EAST

Question 29

A 4.00 kg ball is moving at 4.0 m/s to the right and a 6.00 kg ball is moving at 3.00 m/s to the left.The total momentum of the system is

A) 16 kg m/s to the right.
B) 2.0 kg m/s to the right.
C) 2.0 kg m/s to the left.
D) 18 kg m/s to the left.
E) 34 kg m/s to the left.

Question 30

A 100 kg mass is blown apart into a 50.0 kg piece and a 50.0 kg piece.After the blast,the two masses are moving apart with a relative velocity of 100 m/s.The total kinetic energy after the explosion is

A) 8.42 $\times$ 10⁴ J.
B) 1.25 $\times$ 10⁵ J.
C) 3.62 $\times$ 10⁵ J.
D) 6.50 $\times$ 10⁵ J.
E) 1.24 $\times$ 10⁶ J.

Question 31

A 100 kg mass is blown apart into a 60 kg piece and a 40 kg piece.After the blast,the two masses are moving apart with a relative velocity of 60 m/s.The velocity of the 60 kg mass is

A) 88 m/s.
B) 67 m/s.
C) 51 m/s.
D) 40 m/s.
E) 24 m/s.

Question 32

A 90.kg person is sitting in a boat at rest with a mass of 100 kg.In the boat is a stone with a mass of 5.00 kg.The person throws the stone at 4.00 m/s horizontally in the NORTH direction.The velocity of the person and the boat after the throwing of the stone is

A) 2.00 m/s NORTH.
B) 1.21 m/s SOUTH.
C) 1.21 m/s NORTH.
D) 0.11 m/s SOUTH.
E) 0.11 m/s NORTH.

Question 33

A 5.00 kg ball is moving at 4.0 m/s to the right and a 6.00 kg ball is moving at 3.00 m/s to the left.The total momentum of the system is

A) 2.0 kg m/s to the right.
B) 2.0 kg m/s to the left.
C) 38 kg m/s to the right.
D) 18 kg m/s to the left.
E) 20 kg m/s to the right.

Question 34

A 100.0 kg mass is blown apart into a 95.00 kg piece and a 5.000 kg piece.After the blast,the two masses are moving apart with a relative velocity of 100.0 m/s.The kinetic energy of the 95.00 kg mass after the explosion is

A) 1,190 J.
B) 8,600 J.
C) 18,750 J.
D) 22,560 J.
E) 23,750 J.

Question 35

A 4.00 kg ball is moving at 4.00 m/s to the EAST and a 6.00 kg ball is moving at 3.00 m/s to the NORTH.The total momentum of the system is

A) 14.2 kg m/s at an angle of 48.4 degrees SOUTH of EAST.
B) 48.2 kg m/s at an angle of 24.2 degrees SOUTH of EAST.
C) 48.2 kg m/s at an angle of 48.4 degrees NORTH of EAST.
D) 24.1 kg m/s at an angle of 24.2 degrees SOUTH of EAST.
E) 24.1 kg m/s at an angles of 48.4 degrees NORTH of EAST.

Question 36

An astronaut in a space suit is motionless in outer space.The propulsion unit strapped to her back ejects some gas with a velocity of 40.0 m/s.The astronaut recoils with a velocity of 1.00 m/s.If the mass of the astronaut and space suit after the gas is ejected is 100 kg and the mass of the gas ejected is 2.50 kg,then the total kinetic energy after the ejection of the gas is

A) 2,050 J.
B) 3,430 J.
C) 4,150 J.
D) 5,070 J.
E) 6,320 J.

Question 37

A 100.0 kg mass is blown apart into a 95.00 kg piece and a 5.000 kg piece.After the blast,the two masses are moving apart with a relative velocity of 100.0 m/s.The kinetic energy of the 5.000 kg mass after the explosion is

A) 6,850 J.
B) 7,500 J.
C) 9,570 J.
D) 11,500 J.
E) 22,560 J.

Question 38

A 120 kg mass is blown apart into a 80 kg piece and a 40 kg piece.After the blast,the two masses are moving apart with a relative velocity of 60 m/s.The velocity of the 80 kg mass is

A) 59 m/s.
B) 51 m/s.
C) 34 m/s.
D) 20 m/s.
E) 14 m/s.

Question 39

An airplane has a mass of 8,000 kg and is flying at 150 m/s in level flight.The airplane drops 1,000 kg of water on a fire below.The velocity of the airplane after dropping the water is

A) 50 m/s.
B) 60 m/s.
C) 75 m/s.
D) 100 m/s.
E) 150 m/s.

Question 40

A 4.00 kg ball is moving at 2.00 m/s to the WEST and a 6.00 kg ball is moving at 2.00 m/s to the NORTH.The total momentum of the system is

A) 21.6 kg m/s at an angle of 17.7 degrees NORTH of WEST.
B) 14.4 kg m/s at an angle of 45.2 degrees SOUTH of WEST.
C) 21.6 kg m/s at an angle of 45.2 degrees SOUTH of WEST.
D) 14.4 kg m/s at an angle of 56.3 degrees NORTH of WEST.
E) 21.6 kg m/s at an angle of 56.3 degrees NORTH of WEST.

Question 41

A 4.0 kg object is moving at 5.0 m/s NORTH.It strikes a 6.0 kg object at rest.The objects have an elastic collision and move in the NORTH or SOUTH direction.The velocity of the 4.0 kg object after the collision is

A) 1.0 m/s NORTH.
B) 4.0 m/s NORTH.
C) 1.0 m/s SOUTH.
D) 4.0 m/s SOUTH.
E) 0 m/s.

Question 42

A 4.00 kg mass is moving at 4.00 m/s 45.0 degrees NORTH of WEST and a 6.00 kg mass is moving at 3.00 m/s 30.0 degrees SOUTH of EAST .The velocity of the center of mass is (a),and the velocity NORTH of the center of mass is (b)

A) a = 0.430 m/s,b = 2.30 m/s.
B) a = 1.23 m/s,b = 0.230 m/s.
C) a = 0.430 m/s,b = 0.203 m/s.
D) a = 1.73 m/s,b = 1.43 m/s.
E) a = 0.430 m/s,b = 0.230 m/s.

Question 43

A 4.00 kg object is moving at 5.00 m/s WEST.It strikes a 6.00 kg that is moving WEST at 2.00 m/s.The objects have a one-dimensional elastic collision in the EAST-WEST direction.The velocity of the 6.00 kg object after the collision is

A) 1.40 m/s WEST.
B) 1.40 m/s EAST.
C) 4.40 m/s EAST.
D) 4.40 m/s WEST.
E) 3.00 m/s WEST.

Question 44

Two objects collide and stick together.Which of the following is false?

A) momentum is conserved
B) kinetic energy is lost
C) kinetic energy is conserved
D) momentum is lost

Question 45

A 3.00 kg object is moving at 5.00 m/s EAST.It strikes a 6.00 kg that is moving EAST at 2.00 m/s.The objects have a one-dimensional elastic collision in the EAST-WEST direction.The velocity of the 3.00 kg object after the collision is

A) 4.00 m/s EAST.
B) 1.00 m/s EAST.
C) 4.00 m/s WEST.
D) 1.00 m/s WEST.
E) 3.00 m/s EAST.

Question 46

If a 5.00 kg mass is moving EAST at 10.0 m/s and a 15.0 kg mass is moving WEST at 10 m/s,what is the velocity of the center of mass of the pair?

A) 10 m/s WEST
B) 5.0 m/s EAST
C) 5.0 m/s WEST
D) 10 m/s EAST

Question 47

A 4.00 kg object is moving at 3.00 m/s WEST.It strikes a 6.00 kg that is moving WEST at 2.00 m/s.The objects have a one-dimensional elastic collision in the EAST-WEST direction.The velocity of the 4.00 kg object after the collision is

A) 1.00 m/s WEST.
B) 2.80 m/s EAST.
C) 1.80 m/s WEST.
D) 2.80 m/s WEST.
E) 1.80 m/s EAST.

Question 48

A rocket of length 80 m sits on a launch pad.The center of mass of the rocket is located 32 m above the ground.The rocket is launched to an altitude of 100 km.Where is the location of the center of mass of the total rocket-fuel system at the altitude of 100 km?

A) at ground level
B) 32 m above ground level
C) 40 m above ground level
D) 80 m above ground level
E) 50 km above ground level

Question 49

A 10 kg bomb is moving NORTH with a velocity of 4.0 m/s.It explodes into three fragments: a 5.0 kg fragment moving WEST with a speed of 8.0 m/s,a 4.0 kg fragment moving EAST with a speed of 10 m/s,and a third 1.0 kg fragment.What is the velocity of the third fragment?

A) zero
B) 40 m/s NORTH
C) 40 m/s SOUTH
D) none of these answers are correct

Question 50

Mass 30.0 g is located at the origin.Where is mass 10.0 g located if the coordinates of the center of mass are (0.00 cm,10.0 cm)?

A) (0.00 cm,20.0 cm)
B) (0.00 cm,5.00 cm)
C) (0.00 cm,7.50 cm)

Question 51

A 4.0 kg object is moving at 5.0 m/s NORTH.It strikes a 6.0 kg object at rest.The objects have an elastic collision and move in the NORTH or SOUTH direction.The velocity of the 6.0 kg object after the collision is

A) 0.0 m/s.
B) 1.0 m/s SOUTH.
C) 4.0 m/s SOUTH.
D) 1.0 m/s NORTH.
E) 4.0 m/s NORTH.

Question 52

A 3.00 kg mass is located at x = 2.0 cm and y = 0.0.A 3.00 kg mass is located at x = 0.0 and y = 2.0 cm.A 4.00 kg mass is located at x = 3.0 cm and y = -3.0 cm.Where is the location of the center of mass?

A) (+1.8 cm,-0.60 cm)
B) (+1.8 cm,+0.60 cm)
C) (+0.60 cm,-1.8 cm)
D) (+3.5 cm,-0.6 cm)
E) (+1.8 cm,+1.6 cm)

Question 53

A 8.00 kg mass is moving at 5.00 m/s SOUTH and a 6.00 kg mass is moving at 7.00 m/s EAST.The velocity of the center of mass is (a),and the velocity NORTH of the center of mass is (b)

A) a = +40.0 m/s,b = +3.00 m/s.
B) a = +3.00 m/s,b = +40.0 m/s.
C) a = -3.00 m/s,b = -3.00 m/s.
D) a = +3.00 m/s,b = -40.0 m/s.
E) a = +40.0 m/s,b = -40.0 m/s.

Question 54

A 3.00 kg mass is located at x = 2.0 cm and y = 4.0 cm.A 3.00 kg mass is located at x = -5.0 cm and y = 2.0 cm.A 4.00 kg mass is located at x = 3.0 cm and y = -3.0 cm.Where is the location of the center of mass (x,y)?

A) (0.60 cm,0.30 cm)
B) (0.90 cm,2.0 cm)
C) (3.0 cm,1.0 cm)
D) (0.30 cm,0.60 cm)
E) (3.9 cm,3.0 cm)

Question 55

A 1200 kg car is moving at 5.0 m/s EAST.It strikes an 1800 kg car at rest.The cars have an elastic collision and move in the EAST or WEST direction.The velocity of the 1200 kg car after the collision is

A) 4.0 m /s EAST.
B) 1.0 m/s EAST.
C) 4.0 m/s WEST.
D) 1.0 m/s WEST.
E) 3.00 m/s EAST.

Question 56

A 5.00 kg mass is moving at 4.00 m/s 30.0 degrees SOUTH of WEST and a 2.00 kg mass is moving at 3.00 m/s 60.0 degrees SOUTH of EAST .The velocity of the center of mass is (a),and the velocity NORTH of the center of mass is (b)

A) a = +2.17 m/s,b = -2.05 m/s.
B) a = -2.17 m/s,b = +2.05 m/s.
C) a = +2.05 m/s,b = -2.17 m/s.
D) a = -2.05 m/s,b = +2.17 m/s.
E) a = -2.05 m/s,b = -2.17 m/s.

Question 57

A 3.00 kg mass is located at x = 2.0 cm and y = -4.0 cm.A 3.00 kg mass is located at x = -5.0 cm and y = 2.0 cm.A 4.00 kg mass is located at x = -3.0 cm and y = -3.0 cm.Where is the location of the center of mass (x,y)?

A) (-0.10 cm,-0.50 cm)
B) (-2.1 cm,-1.8 cm)
C) (+2.1 cm,-1.8 cm)
D) (-2.1 cm,+1.8 cm)
E) (+1.1 cm,-2.0 cm)

Question 58

An open box-car has a mass of 30,000 kg and is moving on a level railroad track at 4.00 m/s.1,000 kg of water falls straight down into the box-car.The velocity of the box-car after the water falls into the box-car is

A) 7.01 m/s.
B) 6.55 m/s.
C) 5.02 m/s.
D) 3.87 m/s.
E) 2.89 m/s.

Question 59

A 3.00 kg mass and a 4.00 kg mass are released simultaneously.What is the velocity of the center of mass at t = 10 s (ignore air resistance)?

A) 9.8 m/s
B) 7.0 m/s
C) 70 m/s
D) 98 m/s

Question 60

A 4.00 kg object is moving at 5.00 m/s EAST.It strikes a 5.00 kg that is moving WEST at 2.00 m/s.The objects have a one-dimensional elastic collision in the EAST-WEST direction.The velocity of the 5.00 kg object after the collision is

A) 4.22 m/s EAST.
B) 2.78 m/s WEST.
C) 4.22 m/s WEST.
D) 2.78 m/s EAST.
E) 1.11 m/s WEST.

Question 61

A 4.00 kg object is moving at 5.00 m/s NORTH.It strikes a 6.00 kg object that is moving EAST at 2.00 m/s.The objects have a completely inelastic (stick together)collision.The velocity of the 6.00 kg object after the collision is

A) 2.33 m/s at an angle of 35.0 degrees NORTH of EAST.
B) 2.33 m/s at an angle of 59.0 degrees NORTH of EAST.
C) 2.00 m/s at an angle of 59.0 degrees NORTH of EAST.
D) 2.00 m/s at an angle of 45.0 degrees NORTH of EAST.
E) 2.33 m/s at an angle of 45.0 degrees NORTH of EAST.

Question 62

A 4.00 kg object is moving at 5.00 m/s NORTH.It strikes a 6.00 kg object that is moving WEST at 2.00 m/s.The objects have a completely inelastic (stick together)collision.The velocity of the 4.00 kg object after the collision is

A) 2.54 m/s at an angle of 35.0 degrees NORTH of WEST.
B) 1.93 m/s at an angle of 59.0 degrees NORTH of WEST.
C) 1.93 m/s at an angle of 45.0 degrees NORTH of WEST.
D) 2.33 m/s at an angle of 59.0 degrees NORTH of WEST.
E) 2.33 m/s at an angle of 45.0 degrees NORTH of WEST.

Question 63

A 1700 kg car travels at 20 m/s WEST and collides with a 2000 kg car traveling EAST.The collision is completely inelastic and they both come to rest.What is the velocity of the 2000 kg car?

A) 17 m/s EAST
B) 14 m/s EAST
C) 17 m/s WEST
D) 14 m/s WEST
E) 12 m/s EAST

Question 64

A 4.00 kg object is moving at 5.00 m/s NORTH.It strikes a 6.00 kg object that is moving WEST at 2.00 m/s.The objects have a completely inelastic (stick together)collision.The kinetic energy lost in the collision is

A) 34.8 J.
B) 28.7 J.
C) 20.4 J.
D) 18.7 J.
E) 14.9 J.

Question 65

The Earth has a mass of approximately 80 times that of the Moon.The distance between their centers is on average 384000 km.How far from the center of the Earth is the center of mass of the Earth-Moon system?

A) Not enough information is given
B) 4800 km
C) 4860 km
D) 4740 km

Question 66

A football player leaps at 3.0 m/s toward a second football player,who is at the time of the collision moving at 0.5 m/s toward the first player.After the collision,the two players move together at 1.2 m/s.If the originally stationary player's mass is 175 kg,what is the other's mass?

A) 185 kg
B) 119 kg
C) 165 kg
D) 68 kg

Question 67

A 4.00 kg object is moving at 5.00 m/s NORTHWEST.It strikes a 6.00 kg that is moving SOUTHWEST at 2.00 m/s.The objects have a completely inelastic (stick together)collision.The kinetic energy lost in the collision is

A) 20.4 J.
B) 28.7 J.
C) 34.8 J.
D) 40.2 J.
E) 45.1 J.

Question 68

A ball collides with a second ball at rest.After the collision,the first ball comes to rest and the second ball moves off at the speed of the first ball.In this collision

A) total momentum is not conserved.
B) total kinetic energy is not conserved.
C) total momentum is conserved but total kinetic energy is not conserved.
D) total momentum is not conserved but total kinetic energy is conserved.
E) total momentum and total kinetic energy are conserved and the masses are equal.

Question 69

In any collision

A) total momentum is not conserved.
B) total kinetic energy is conserved.
C) total momentum is conserved.
D) total momentum is not conserved but total kinetic energy is conserved.
E) total momentum and total kinetic energy are conserved and the masses are equal.

Question 70

A binary star system is composed of two stars (one blue,one red)that orbit a common point: the center of mass of the system.The distances from the stars to the center of mass might be labeled r_blue and r_red.The sum of the masses of the stars is M_blue + M_red = 3.70 $\times$ 10³³ kg.If it is known that r_blue = 2/5 r_red,what is M_red?

A) 1.06 $\times$ 10³³ kg
B) 2.64 $\times$ 10³³ kg
C) 1.48 $\times$ 10³³ kg
D) 2.22 $\times$ 10³³ kg

Question 71

A 4.00 kg object is moving at 5.00 m/s NORTHWEST.It strikes a 6.00 kg that is moving SOUTHWEST at 2.00 m/s.The objects have a completely inelastic (stick together)collision.The velocity of the 6.00 kg object after the collision is

A) 2.33 m/s at an angle of 45.0 degrees NORTH of WEST.
B) 3.89 m/s at an angle of 35.0 degrees NORTH of WEST.
C) 3.89 m/s at an angle of 14.0 degrees NORTH of WEST.
D) 2.33 m/s at an angle of 14.0 degrees NORTH of WEST.
E) 2.33 m/s at an angle of 35.0 degrees NORTH of WEST.

Question 72

A 4.00 kg object is moving at 5.00 m/s EAST.It strikes a 6.00 kg that is at rest.The objects have an elastic collision.The velocity of 4.00 kg object after the collision is in the SOUTHWEST direction.The velocity of the 6.00 kg object after the collision is

A) 2.38 m/s.
B) 3.02 m/s.
C) 3.51 m/s.
D) 4.06 m/s.
E) 5.22 m/s.

Question 73

A 1200 kg car travels at 25.0 m/s and collides head-on in a perfectly inelastic collision with a stationary 2400 kg truck.The kinetic energy lost in the collision is

A) 330,000 J.
B) 250,000 J.
C) 125,000 J.
D) 95,000 J.
E) 75,000 J.

Question 74

A 1200 kg car is moving at 5.0 m/s EAST.It strikes an 1800 kg car at rest.The cars have an elastic collision and move in the EAST or WEST direction.The velocity of the 1800 kg car after the collision is

A) 3.0 m/s WEST.
B) 1.0 m/s EAST.
C) 4.0 m/s EAST.
D) 4.0 m/s WEST.
E) 1.0 m/s WEST.

Question 75

A 4.00 kg object is moving at 5.00 m/s EAST.It strikes a 6.00 kg that is at rest.The objects have an elastic collision.The velocity of the 4.00 kg object after the collision is at an angle of 30.0 degrees SOUTH of EAST.The velocity of the 4.00 kg mass after the collision is

A) 5.78 m/s.
B) 4.56 m/s.
C) 3.55 m/s.
D) 1.67 m/s.
E) 2.66 m/s.

Question 76

A vertical spring is compressed and when released applies a force during a 0.25 s time interval to a 17 g frog,which is flung upward due to the applied force from the spring.If the frog attains a velocity of 11 m/s after being released from the spring,what average force was applied by the spring?

A) 0.21 N
B) 0.91 N
C) 0.75 N
D) 0.17 N
E) 0.58 N

Question 77

A 4.00 kg object is moving at 5.00 m/s SOUTH.It strikes a 3.00 kg object that is moving WEST at 2.00 m/s.The objects have a completely inelastic (stick together)collision.The kinetic energy lost in the collision is

A) 20.2 J.
B) 18.4 J.
C) 10.5 J.
D) 8.33 J.
E) 2.61 J.

Question 78

A 1500 kg car accelerates from rest to 35 m/s in 6.5 s.If its engine and tires are able to provide a force to the car of 8500 N,what was the magnitude of the sum of forces due to friction and air resistance on the car during this interval?

A) 11450 N
B) 1840 N
C) 3510 N
D) 3150 N

Question 79

A 2200 kg truck is decelerated from 22 m/s to 12 m/s in 3.2 s,as its driver sees a deer wander into the road.What was the magnitude of the net force that slowed the truck?

A) 8.3 kN
B) 23.4 kN
C) 6.9 kN
D) 15.1 kN

Question 80

A 1200 kg car is moving at 5.0 m/s EAST.It strikes an 1800 kg car at rest.The cars have an elastic collision and move in the EAST or WEST direction.The relative velocity between the cars after the collision is

A) 3.0 m/s WEST.
B) 1.0 m/s EAST.
C) 4.0 m/s EAST.
D) 5.0 m/s EAST.
E) 1.0 m/s WEST.