Unit 5 Review

A block of mass M is placed at height H. A block of mass 2M is placed at the same height. How does the PE of the second block compare to the first?

• 1/2 PE

• PE

• 2 PE

• 4 PE

Answer explanation

Potential is directly related to height AND mass

Tags

NGSS.MS-PS3-2

A firefighter carrying his gear has a total weight of 1200 N. How much work does he do when he climbs a 20 m ladder in 15 sec? (HINT: W = F*d)

• 60 J

• 120 J

• 6000 J

• 24000 J

Answer explanation

Since Work = Force*Distance, we multiply our force (vertical - our weight) times our distance (vertical - going UP the ladder)

Mr. Elliott wants to see if energy is conserved by rolling a marble down a ramp. What needs to be true for energy to be conserved?

• KE at the end should match the initial PE

• KE should be higher at all times

• There should be no KE

• It is always conserved

Answer explanation

Friction can take away our energy. It is conserved if the total initial energy is equal to the total final energy.

Tags

NGSS.MS-PS3-5

NGSS.MS-PS3-4

Using the graph, what can we tell about potential energy?

• Increases

• Decreases

• Stays the same

• Not enough information

Answer explanation

If KE is increasing, our PE must decrease for out total energy to be the same

Tags

NGSS.MS-PS3-2

There are 3 carts. Cart A is 1 kg, Cart B is 2 kg, and Cart C is 3 kg. If they are all at a height of 20 m, which cart will have the highest KE when it falls down?

• Cart A

• Cart B

• Cart C

• All the same

Answer explanation

The one that has the most PE in the beginning will have the most KE in the end

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-4

There are 3 carts. Cart A is 1 kg, Cart B is 2 kg, and Cart C is 3 kg. If they are all at a height of 20 m, which cart will have the most PE?

• Cart A

• Cart B

• Cart C

• All the same

Answer explanation

PE is based on height and mass

A block is sliding across a table. If the block is losing kinetic energy, what type of force is acting on it?

• Conservative

• Non-conservative

• Gravity

• Tension

Answer explanation

if you lose energy, then energy is not conserved. The only force we know that does that is friction

Tags

NGSS.MS-PS3-5

NGSS.MS-PS3-1

Imagine you are on a rollercoaster doing firsthand experiments with energy. At which point will you have the highest PE?

• The top

• The bottom

• The middle

• It is equal everywhere

Answer explanation

PE is based on the HEIGHT and the mass

Tags

NGSS.MS-PS3-2

Imagine you are on a rollercoaster doing firsthand experiments with energy. At which point will you have the highest KE?

• The top

• The bottom

• The middle

• It is equal everywhere

Answer explanation

KE and PE are inverse. KE is highest when PE is the lowest (at the bottom)

Tags

NGSS.MS-PS3-5

NGSS.MS-PS3-1

NGSS.MS-PS3-4

Imagine you are on a rollercoaster doing firsthand experiments with energy. What has to be true for energy to be conserved?

• A lot of friction

• No friction

• It is always conserved

Answer explanation

Friction is the only thing that takes away our energy

Tags

NGSS.MS-PS3-5