physics chapter 7: linear momentum

When a constant force acts on an object, what does the object's change in momentum depend upon?

-The change in momentum depends upon the mass of the object. -The change in momentum depends upon the time interval during which the force acts. -The change in momentum depends upon the change in the velocity of the object. -The change in momentum depends upon the magnitude of the force

Two air track carts move along an air track towards each other. Cart A has a mass of 450 g and moves toward the right with a speed of 0.850 m/s. Cart B has a mass of 300 g and moves toward the left with a speed of 1.12 m/s. What is the total momentum of the two-cart system?

0.047 kg. m/s toward the right

A 100-g ball falls from a window that is 12 m above ground level and experiences no significant air resistance as it falls. What is its momentum when it strikes the ground?

1.5 kg. m/s

A 2.0-kg ball moving eastward at 3.0 m/s suddenly collides with and sticks to a 4.0-kg ball moving northward at 2.0 m/s. What is the magnitude of the momentum of this system just after the collision?

10 kg * m/s

A tiger is running in a straight line. If we double both the mass and speed of the tiger, the magnitude of its momentum will increase by what factor?

4

If you want to double the momentum of a gas molecule, by what factor must you increase its kinetic energy?

4

A golf club exerts an average horizontal force of 1000 N on a 0.045-kg golf ball that is initially at rest on the tee. The club is in contact with the ball for 1.8 ms. What is the speed of the golf ball just as it leaves the tee?

40 m/s

A 5-kg ball collides inelastically head-on with a 10-kg ball, which is initially stationary. Which of the following statements is true? (There is more than one correct choice.)

A) The magnitude of the change of velocity the 5-kg ball experiences is greater than that of the 10-kg ball. D) The magnitude of the change of the momentum of the 5-kg ball is equal to the magnitude of the change of momentum of the 10-kg ball.

There must be equal amounts of mass on both sides of the center of mass (or center of gravity) of a system.

False

units for momentum?

N * m kg * m/s

A very light ping-pong ball moving east at a speed of 4 m/s collides with a very heavy stationary bowling ball. The Ping-Pong ball bounces back to the west, and the bowling ball moves very slowly to the east. Which object experiences the greater magnitude impulse during the collision?

Neither; both experienced the same magnitude impulse

A firecracker explodes in midair and breaks up into many fragments. Which of the following statements are true regarding conditions immediately before and immediately after the explosion: I: The total momentum of the fragments is equal to the original momentum of the firecracker. II: The total kinetic energy of the fragments is equal to the original kinetic energy of the firecracker.

Statement 1 only

What represents the impulse of the force in a graph of force versus time?

The area under the curve

Consider two less-than-desirable options. In the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. In the second option you are driving 30 mph and crash head-on into a stationary brick wall. In neither case does your car bounce back from the thing it hits, and the collision time is the same in both cases. Which of these two situations would result in the greater impact force on your car?

The force would be the same in both cases.

A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the momentum during the collision are correct?

The momentum of the car-truck system is constant, but the momentum of each one separately is not constant

A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the magnitude of the momentum change during the collision is correct?

The small car and the truck experience the same magnitude momentum change

A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the magnitude of the average force during the collision is correct?

There is the same magnitude average force exerted on both the small car and the truck.

Three cars, car X, car Y, and car Z, begin accelerating from rest at the same time. Car X is more massive than car Y, which is more massive than car Z. The net accelerating force exerted on each car is identical. After 10 seconds, which car has the most amount of momentum?

They all have the same amount of momentum

Three cars, car X, car Y, and car Z, begin accelerating from rest at the same time. Car X is more massive than car Y, which is more massive than car Z. The net accelerating force exerted on each car is identical. After 10 seconds, which car has the most amount of momentum?

They all have the same amount of momentum.

In a collision between two objects of unequal mass, which object receives a greater magnitude impulse?

They receive equal magnitude impulses.

If both the graph representing the constant net force and the graph representing the variable net force represent the same impulse acting on the baseball, which geometric properties must the two graphs have in common?

area

In a game of pool, the white cue ball hits the #5 ball and stops, while the #5 ball moves away with the same velocity as the cue ball had originally. Both balls have the same mass. The type of collision is

elastic

Identical forces are exerted for the same length of time on two different objects. The magnitude of the change in momentum of the lighter object is

exactly equal to the magnitude of the change in momentum of the larger mass object.

What are the units for impulse?

kg *m/s N * s

If you want to double the kinetic energy of a gas molecule, by what factor must you increase its momentum?

sqr. rt. of 2

Two friends are standing on opposite ends of a canoe that is initially at rest with respect to a frictionless lake. The person in the front throws a very massive ball toward the back, and the person in the back catches it. After the ball is caught, the canoe is

stationary

The magnitude of the net force versus time graph has a rectangular shape. Often in physics geometric properties of graphs have physical meaning.

the area of the rectangle corresponds to the impulse

A rubber ball and a lump of clay have equal mass. They are thrown with equal speed against a wall. The ball bounces back with nearly the same speed with which it hit. The clay sticks to the wall. Which one of these objects experiences the greater momentum change?

the ball

Two objects of different mass have equal, non-zero kinetic energies. Which object has the greater magnitude momentum?

the heavier object

Two objects of different masses have momentum of equal, non-zero magnitude. Which object has more kinetic energy?

the lighter object

A rocket explodes into two fragments, one 25 times heavier than the other. The magnitude of the momentum change of the lighter fragment is

the same as the momentum change of the heavier fragment.