Physics - Equations

Question 1

Acceleration =

Answer 1

( final velocity - initial velocity ) divided by time
A= (v-u)/t
Unit= m/s (squared)

Question 2

Resultant force =

Newton’s Second Law

Answer 2

Mass x Acceleration
F=ma
Unit = N, Newtons

Question 3

Weight =

Answer 3

Mass x gravitational field strength
W=mg
Unit = N, Newtons

Question 4

Momentum =

Answer 4

Mass x velocity
P=mv
Unit= kg m/s

Question 5

Force =

Momentum

Answer 5

Changing in momentum divided by time
P= (mv-mu)/t
Unit = N, Newtons

Question 6

Distance travelled =

Answer 6

Average speed x time
D= s x t
Unit= m

Question 7

Change in gravitational potential energy =

Answer 7

Mass x gravitational field strength x change in height
(change in) GPE=mgh
Unit= J, Joules

Question 8

Kinetic energy =

Answer 8

1/2 x mass x velocity squared
KE= 1/2 x m x v (squared)
Unit= J, Joules

Question 9

Efficiency =

Answer 9

Useful energy in divided by total energy out times 100
OR
Useful power divided by total power times 100

Question 10

Wave speed =

Answer 10

Frequency x wavelength 
V= f x wavelength (upside down y )
                                  OR 
Distance/ time ( v= x/t ) 
Unit= m/s

Question 11

Work done =

Answer 11

Force x distance moved in the direction of the force I
E= fd
(FED, Force = Work done x distance )
Unit= J, Joules

Question 12

Power =

Answer 12

Work done divided by time taken
P= e/t
Unit= W, Watts

Question 13

Energy transferred =

Electrically

Answer 13

Charge moved x potential difference (voltage)
E= Q x V
Unit= J,Joules

Question 14

Potential difference (voltage)=

Answer 14

Current (amperes or amps) x resistance (ohms)
V= IR
Unit= V, Volts

Question 15

Electrical power =

Answer 15

Current x voltage
P=IV
Unit= W,Watts

Question 16

Energy transferred =

Answer 16

Current x velocity x time
E= IVT ( ITV)
Unit= J,Joules

Question 17

Stopping distance =

Answer 17

Thinking distance + braking distance

Question 18

Change in thermal energy =

Answer 18

Mass x specific heat capacity x temperature change
Q= m x c x °c
Unit= J,Joules

Question 19

Thermal energy =

Answer 19

Mass x specific latent heat
Q= m x L
Unit= J,Joules

Question 20

Time period =

Answer 20

1 divided by Frequency
1/f
Unit= s, seconds

Question 21

Frequency =

Answer 21

1 divided by time
1/t
Units= Hz, Hertz

Question 22

Speed =

Answer 22

Distance / time

V= x/t

Question 23

Density=

Answer 23

Mass/volume
P= m/v
Units= g/cm(cubed) OR kg/m(cubed)

Question 23

Final velocity - initial velocity =

Answer 23

2 x acceleration x distance

V squared - u squared = 2ax

Question 24

Force =

Magnets

Answer 24

Magnetic flux density x current x length ( l )
F= B x I x l
Unit= N, Newtons

Question 25

Force exerted on a spring=

Answer 25

Spring constant (N/m) x extension (m)
F= kx 
Unit= N,Newtons

Question 26

Energy transferred in stretching=

Answer 26

1/2 x spring constant x extension squared
E= 1/2 x k x x squared
Unit= J,Joules

Question 27

Charge=

Answer 27

Current x time
Q= It
Unit= C,Coulombs

Question 28

Electrical Power =

Answer 28

Current squared x Resistance
P= I^2 x R
Unit= Watts, W