# Section 2 - General Physics: Energy and Pressure Flashcards

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1
Q

All 7 energy store

A

Kinetic - anything moving
Gravitational potential - anything that fall
Chemical - anything that releases energy through chemical reaction
Elastic - anything stretched
Nuclear - Atomic nuclei release energy from this in nuclear reactions
Electrostatic - two charges that attract or repel
Thermal - any object, hotter objects have more

2
Q

Principle of conservation of energy

A

The principle of conservation of energy states that energy can be stored, transferred from one store to another, or dissipated - but it can never be created or destroyed.

3
Q

4 ways of energy transfer

A
1. Mechanically - work is done by a force acting on an object
2. Electrically - work is done by an electric current flowing
3. By waves - energy transferred by waves like sound and light
4. By heating - energy transferred from a hotter to colder object
4
Q

Kinetic energy equation - energy whilst moving

A

Depends on mass and speed

Kinetic energy = 0.5 x mass(kg) x speed(m/s) squared
Ek = 0.5mv^2

5
Q

GPE equation - raised objects store energy

A

Change in GPE = mass(kg) x gravity(9.8N/kg) x change in height(m)
Change in GPE = mgh

6
Q

What is work

A

Work done is equal to energy transferred

7
Q

Work done formula

A

Work done = force x distance = energy transferred
W = Fd = change in E

8
Q

Power

A

Power is the work done or the energy transferred per unit time

9
Q

Power equation - energy transfer

A

Power(W) = energy transferred(J) / time taken(s)
P = E change / time

10
Q

Efficiency

A

The efficiency of a process or device is a measure of the proportion of the input energy that is transferred usefully

11
Q

Efficiency equation

A

Efficiency = useful energy output / total energy input x 100