chapter 7 - impulse and momentum

IV only

two objects have the same momentum. which of the following is true?

I. the masses of the objects are equal

II. the speeds of the objects are equal

III. the velocities of the objects are equal

IV. the direction of motion of each object is the same

none of the above

a group of particles has a net momentum equal to zero. which of the following must be true?

I. the speed of each particle is zero

II. the velocity of each particle is zero

III. the mass of each particle must be equal

IV. the kinetic energy of each particle must be zero

c

you are a passenger on a jet liner that is flying at constant velocity. you get up from your seat and walk toward the front of the plane. because of this action, your forward momentum increases. what happens to the forward momentum of the plane itself?

a) it remains constant

b) it increases

c) it decreases

II only

exploding gunpowder in a cannon (mass M) propels a cannonball (mass m) forward. simultaneously, the cannon recoils. which of the following is true? note that M > m.

I. the speeds of the cannonball and cannon are equal

II. the magnitudes of the momentum of the cannonball and cannon are equal

III. the kinetic energy of the cannonball and cannon are equal

f

t/f

in an elastic collision, the kinetic energy of each object is the same both before and after the collision

b

a car of mass m moving with speed v collides with an identical car that is at rest. after the collision, the cars stick together. which of the following statements is false?

a) the total momentum before and after the collision is conserved

b) the total kinetic energy before and after the collision is conserved

c) the collision is completely inelastic

d) the speed of the cars after the collision is v/2

f

t/f

in a two-dimensional collision, momentum can only be conserved in one dimension, not both

a

object 1 is moving in the positive x direction. it collides with a second object that is initially at rest. the collision is not head on, so the objects move off in different directions after the collision. what must be true about the total momentum of object 1 and object 2 in the y-direction after the collision?

a) the total momentum in the y-direction after the collision will be equal to zero

b) the total momentum in the y-direction after the collision will point in the negative y-direction, because object 1 has a greater speed after the collision

c) the total momentum in the y-direction after the collision will point in the positive y-direction, because object 2 has a greater mass

b

two particles are located on the x-axis as shown. particle 1 has a mass of 3m, and particle 2 has a mass of m. where on the x-axis, as indicated by the letters A, B, C, D, is closest to the center of mass of this system?

c

the figure below shows the top view of two balls colliding on a horizontal frictionless table. the path followed by the center of mass of this system is shown by the black vector. which path, labeled A, B, C, D, will the center of mass follow after the collision?