P4 - Kinetic Energy And GPE

Question 1

What is the formula for KE?

Answer 1

KE (J) = 1/2 x mass (kg) x velocity squared (m/s 2)

Question 2

How does kinetic energy work?

Answer 2

For velocity to increase, there needs to be a resultant force meaning that work needs to be done. This causes the KE to increase. The GPE is converted into kinetic energy as an object falls. If the object doesn’t accelerate, it hasn’t gained KE.

Question 3

Why is increase in KE slightly less than the GPE?

Answer 3

Some energy is wasted as HEAT due to friction and air resistance, as well as sound!

Question 4

In space why is the increase in KE equal to GPE lost?

Answer 4

There is no friction or air resistance.

Question 5

How does gravitational potential energy work?

Answer 5

This is energy stored when an object is lifted against the force of gravity. If an object is lifted, GPE is gained. As it falls, it loses GPE and this is converted into kinetic energy which makes the object gain speed as the KE increases causing the object to accelerate. When KE is converted to GPE, assume no energy is lost as waste.

Question 6

What is the GPE equation?

Answer 6

GPE (J) = Weight (N) * vertical height difference (m)

Question 7

How does work done work?

Answer 7

The thing exerting the force receives energy (food or fuel), which causes the force to be exerts onto an object with this energy. This means energy is transferred either usefully to move the object, or it is wasted as heat. The object doing work loses energy.

Question 8

Work done (J) equals…

Answer 8

Energy transferred (J)

Question 9

What is the formula for work done?

Answer 9

Work done (J) = force (N) x distance in a set direction (m)