Equations

Question 1

Pressure?

Answer 1

Force / area

P = F/A

Question 2

Distance travelled?

Answer 2

Speed x time

S = v t

Question 3

Acceleration?

Answer 3

Change in velocity / time taken

a = v - u / t

Question 4

Wave speed?

Answer 4

Frequency x wavelength

V = f a

Question 5

Charge?

Answer 5

Current x time

Q = I t

Question 6

Potential difference?

Answer 6

Current x resistance

V = I R

Question 7

Electrical Power (1)?

Answer 7

Potential difference x current

P = V I

Question 8

Power (2)?

Answer 8

(Current²) x resistance

P = I²R

Question 9

General power?

Answer 9

Energy transferred / time

P = E/t

Question 10

Energy transferred?

Answer 10

Charge x potential difference

E = Q V

Question 11

Density?

Answer 11

Mass / volume

rho = m/v

Question 12

Period?

Answer 12

1 / frequency

Question 13

Boyle’s Law?

Answer 13

pV = constant

Question 14

Newton’s 2nd Law?

Answer 14

Acceleration = force / mass

a = F / m

Question 15

Weight?

Answer 15

Mass x gravitational field strength

w = m g

Question 16

Work done?

Answer 16

Force x distance moved

W = F D

Question 17

Hooke’s law?

Answer 17

Force = spring constant x spring extension

F = k e

Question 18

Resistance?

Answer 18

Potential difference / Current

R = V/I

Question 19

Efficiency?

Answer 19

Useful energy / Energy put in x100

E= useful/input x100

Question 20

Kinetic energy?

Answer 20

1/2 x Mass x Speed²

Ek=1/2mv²

Question 21

Gravitational potential energy?

Answer 21

Mass x Gravitational field strength x Height

Ep=mgh

Question 22

Velocity²?

Answer 22

Initial velocity² + 2 x Acceleration x Displacement

v²=u²+2as

Question 23

Elastic potential energy?

Answer 23

1/2 x Spring constant x Extension²

Ee=1/2ke²

Question 24

Specific heat capacity?

Answer 24

Energy / mass x temperature change

c = E / m x temp.

Question 25

Specific latent heat?

Answer 25

Energy / mass l = E / m

Question 26

Pay back time?

Answer 26

Cost of insulation / Annual saving

Question 27

No. of units used?

Answer 27

Power x Time Pt

Question 28

Total cost of electricity?

Answer 28

No. of units used x Unit price

Question 29

Transformer?

Answer 29

Np/Ns = Vp/Vs

Question 30

Moments?

Answer 30

M = F x d

Question 31

Pressure at a certain depth due to the column of liquid above?

Answer 31

Pressure = depth x field strength x density p=hρg

Question 32

Momentum?

Answer 32

Mass x Velocity m = m x v

Question 33

Force (in terms of momentum)?

Answer 33

Change in momentum / time taken F = ΔP / Δt