Energy- P1- Paper 1

Question 1

Name the 8 energy stores.

Answer 1

-Thermal
-Kinetic
-Gravitational potential
-Elastic potential
-Chemical
-Magnetic
-Electrostatic
-Nuclear

Question 2

Name the 4 ways energy can be transferred.

Answer 2

1. Mechanically (force doing work)
2. Electrically (work done by moving charges
   3+4. Heating or radiation (light or sound)

Question 3

What is a closed system?

Answer 3

A single object or a group of objects.

Question 4

What effect does energy transfer have on a system?

Answer 4

The system changes.

Question 5

How can a systems energy be transferred?

Answer 5

1. Into or away from the system
2. Between different objects in the system
3. Between different energy stores

Question 6

What are closed systems?

Answer 6

A system where neither matter nor energy can enter or leave.

Question 7

Describe the energy transfers that occur when the wind causes a windmill to spin. [3 marks]

Answer 7

Energy is transferred mechanically from the kinetic energy of the wind to the **kinetic energy of the windmill.

Question 8

What is kinetic energy? [3 points]

Answer 8

Anything that is moving has energy in its kinetic energy store.
Energy is transferred to the store when an object speeds up.
Energy is transferred away from the store when an object slows down.

Question 9

Define kinetic energy.

Answer 9

The greater its mass and the faster its going, the more energy there will be in its kinetic energy store.

Question 10

What is the formula for kinetic energy.

Answer 10

Kinetic energy (J) = 1/2 x mass (kg) x speed2 (m/s)2

Question 11

What is gravitational field strength.

Answer 11

The force acing on an object when it’s raised. The higher the object is lifed, the more energy is transferred to this store.

Question 12

How does mass, height and strength affect and objects GPE?

Answer 12

As the object gets heavier/ higher up/ the GF gets stronger the GPE will have more energy stored.

Question 13

What is the equation for GPE?

Answer 13

GPE (J) = mass (Kg) x GFS (N/kg) x height (m)

Question 14

What energy transfers occur to a closed system when falling?

Answer 14

Energy from its GPE store will transfer to its kinetic Energy store.

Question 15

That will happen to an objects energy while it is falling?

Answer 15

It’s energy will transfer from its GPE store to its kinetic energy store but due to air resistance some energy will be lost to other store’s e.g. the thermal energy stores of the object and its surroundings.

Question 16

When is energy transferred to an objects Elastic potential store?

Answer 16

When it is stretched or squashed.

Question 17

When elastic limit hasn’t been reached, what is the equation for elastic potential energy?

Answer 17

Elastic potential energy (J) = 1/2 x spring constant (N/m) x extension2 (m)2

Question 18

A 2.0Kg object is dropped from a height of 10m.
Calculate the speed of the object after it has fallen 5.0m, assuming there is no air resistance.
Give our answer to 2 significant figures. G=9.8 N/kg.
[5 marks]

Answer 18

Ep= mgh (sub in the change in height instead as your looking for it at 5m but its fallen from 10)
Ep= 2x9.8x5
Ep= 98J. [1 mark]

No air resistance so Ep=Ek
So, Ek= 98J [1 mark]

Ek= 1/2mv2 (but we want the speed so you have to rearrange it.)
2Ek/m=v2 [1 mark]

V2= (2x98)/2.0 [1 mark]
(we don’t need to do the full equation as we can see that the 2 on the top and bottom cancle each other out)
V2= 98m2/s2

(square root it)
V= 9.899…m/s
(put to 2 s.f.)
= 9.9m/s