Momentum and Center of Mass

An object of mass m =2 kg experiences a force as shown in the force-time graph. Over the 5 seconds, what is the total change in momentum?

• 35 kg m/s

• 70 kg m/s

• -35 kg m/s

• -70 kg m/s

• None of these

Tags

NGSS.HS-PS2-1

A cannon is mounted on a cart, and carrying a cannonball. The total mass of the cart, cannon, and ball is M, and the cart is rolling with no friction at a velocity v in the positive x-direction as shown above. The ball, of mass m, is fired with a velocity of vball in the positive x direction. What is the velocity of the cart and cannon after the ball is fired?

• (Mv-mv_ball)/(M-m_ball)

• (Mv-mv_ball)/M

• (v-mv_ball)/m_ball

• (Mv+mv_ball)/(M-m_ball)

• (-Mv-mv_ball)/(M+m_ball)

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-2

In a laboratory experiment, a cart rolling frictionless across a table collides with a sensor that indicates both the net force acting on the cart during the collision and the time over which the collision occurred. Based on this information, one can calculate:

• the acceleration of the cart

• the momentum of the cart

• the mass of the cart

• the change in kinetic energy

• the change in momentum of the cart

Tags

NGSS.HS-PS2-1

An air track glider of mass M is built, consisting of two smaller connected gliders with a small explosive charge between them. The glider is traveling along a frictionless rail at 2 m/s to the right when the charge is detonated, causing the small glider with mass 1/4 M to move off to the right at 5 m/s. What is the final velocity of the second glider?

• 4 m/s to the left

• 2m/s to the left

• 1 m/s to the left

• 0 m/s

• 1 m/s to the right

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-2

A billiard ball hits the side of the pool table at an angle shown and bounces away at the same angle and same speed. What is the direction of the net change in momentum of the billiard ball?

• Northeast

• East

• Southeast

• South

• Southwest

Tags

NGSS.HS-PS2-2

A force acting on an object varies as a function of time according to the equation F=kt² where k is a constant. If the object had an initial momentum of 0 at time t=0, what is the momentum of the object at time t?

• 2t

• 2kt

• (1/2)kt³

• (1/3)kt³

• (1/3)kt²

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-2

Two ice skaters of mass 30 kg and 80 kg are skating across the surface of a frozen lake on a collision course with respective velocities of 2 m/s in a general north direction and 1 m/s generally west as shown. After they collide, the pair of skaters move off with a momentum of 100 kg m/s in a direction north of west. How much kinetic energy was lost in the collision?

• 0 J

• 110 J

• 55 J

• 70 J

• 120 J

Tags

NGSS.HS-PS2-2

A large cannon is mounted on a cart with frictionless wheels that is initially at rest on a horizontal surface. The cannon fires a large cannonball to the right with a speed v_cannonball which is then caught by a trap firmly attached to the cart. What is the final speed of the cannon-cart-cannonball system?

• v>v_cannonball to the left

• v>v_cannonball to the right

• 0

• v<v_cannonball to the left

• v<v_cannonball to the right

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-2

A soccer ball is rolling along a field with speed +vinitial when a student runs up and kicks the ball in the same direction that it was traveling so that it now has a greater speed in the same direction, +vfinal. Your physics teacher warns you to take measurements that will allow you to calculate a rough estimate of the impulse applied to the ball by the student's foot. Which measurement would you want to make so that you could calculate this impulse?

I. the distances and times the ball traveled, both before and after the kick

II. the mass of the ball

III. the force applied to the ball

IV. the time that the foot and ball were in contact.

• I and II

• I and III

• I and IV

• II and III

• II and IV

Tags

NGSS.HS-PS2-1

There is an elastic collision as shown. Which pictures shows the correct motion of the pucks after the two dimensional elastic collision occurs?

• A

• B

• C

• D

• E

Tags

NGSS.HS-PS2-2