An open cart rolls along a frictionless track while it is raining. As it rolls, what happens to the speed of the cart as the rain collects in it? (assume that the rain falls vertically into the box)

• stops immediately

• maintains constant speed

• speeds up

• slows down

A system of particles is known to have a total momentum of zero. Does it necessarily follow that the total kinetic energy of the system is also zero?

• yes

• no

Two objects are known to have the same momentum. Do these two objects necessarily have the same kinetic energy?

• yes

• no

A small car and a large truck collide head-on and stick together. Which one has the larger momentum change?

• the car

• the truck

• they both have the same momentum change

Two boxes, one heavier than the other, are initially at rest on a horizontal frictionless surface. The same constant force F acts on each one for exactly 1 second. Which box has more momentum after the force acts ?

• the heavier one

• both the same

• the lighter one

In the previous question, which box has the larger velocity after the force acts?

• both the same

• the heavier one

• the lighter one

A small beanbag and a bouncy rubber ball are dropped from the same height above the floor. They both have the same mass. Which one will impart the greater impulse to the floor when it hits?

• the beanbag

• the rubber ball

• both the same

Two objects, P and Q, have the same momentum. Q can have more kinetic energy than P if it has:

• More mass than P 
• The same mass as P 
• More speed than P 
• The same speed as P 

Tags

NGSS.HS-PS2-2

A car of mass m, traveling at speed v, stops in time t when maximum braking force is applied. Assuming the braking force is independent of mass, what time would be required to stop a car of mass 2m traveling at speed v?

• ½t
• t
• √2 t
• 2t

Tags

NGSS.HS-PS2-1

Two football players with mass 75 kg and 100 kg run directly toward each other with speeds of 6 m/s and 8 m/s respectively. If they grab each other as they collide, the combined speed of the two players just after the collision would be:

• 2 m/s 
• 3.4 m/s 
• 4.6 m/s 
• 7.1 m/s

Tags

NGSS.HS-PS2-2