Momentum and Energy

Momentum = mass x velocity. Inertia is greater for more massive objects. Cart A has a mass of 2 kg and a speed of 3 m/s. Cart B has a mass of 3 kg and a speed of 2 m/s. Compared to cart A, cart B has

• the same inertia and a smaller momentum

• the same inertia and the same momentum

• greater inertia and a smaller momentum

• greater inertia and the same momentum

A rocket engine gains motion by ejecting hot gases in the opposite direction. This is an example of the law of

• Conservation of Heat

• Conservation of Energy

• Conservation of Momentum

• Conservation of Mass

Tags

NGSS.MS-PS2-1

In the diagram shown, a clump of clay travels horizontally to the right and collides with a block at rest on a frictionless surface. After collision, they stick together and move to the right. Compared to the total momentum of the clay and the block before the collision, the momentum of the clay+block system after collision is

• less

• more

• the same

• twice as much

Tags

NGSS.MS-PS2-1

Which action would require no work to be done on an object?

• lifting the object from the floor to the ceiling

• pushing the object from the window to the wall

• decreasing the speed of an object until it comes to a stop

• standing still holding an object

In the diagram, a 20 N force is used to push a 2 kg cart a distance of 5 meters. What is the work done on the cart?

Work = Force x displacement

• 100 J

• 110 J

• 40 J

• 10 J

Tags

NGSS.MS-PS2-2

Which unit is equivalent to a watt, the SI unit of Power?

• joule/sec

• joule x sec

• newton/sec

• newton x sec

If the velocity of a moving object is doubled, the object's kinetic energy is

• the same

• two times as big

• half as big

• four times as big

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-5

A shopping cart slows as it moves across a level floor. Which statement describes the energies of the cart?

• The kinetic energy increases and the gravitational potential energy remains the same.

• The kinetic energy decreases and the gravitational potential energy remains the same.

• The kinetic energy increases and the gravitational potential energy decreases.

• The kinetic energy decreases and the gravitational potential energy increases.

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Two students of equal weight go from the first floor to the third floor. One student uses the stairs. The second student uses the elevator. Compared to the potential gravitational energy gained by the first student, the potential gravitational energy of the second student is

• less

• greater

• the same

• not enough information is given

Three people of equal mass climb a mountain using paths A, B and C as shown in the diagram. Along which path does a person gain the most gravitational potential energy from start to finish.

• A, only

• B, only

• C, only

• The gain is the same along all paths

Tags

NGSS.MS-PS3-2