Key equations

Question 1

Average speed =

Answer 1

Distance / time

Question 2

Distance =

Answer 2

Average speed x time

Question 3

Acceleration =

And another version which starts with v^2 - u^2 = …

Answer 3

Change in velocity / time taken
a= (v-u)/t
V^2 - u^2 = 2 x a x X
X stands for distance

Question 4

What is Newton’s second law? The equation for force?

Answer 4

F=m x a

Question 5

Weight=

Answer 5

Mass x gravitational field strength

W = m x g

Question 6

What is Earths gravitational field strength?

Answer 6

10 N/kg

9.81 rounded

Question 7

Momentum =

Answer 7

Mass (kg) x velocity

P = m x v

Question 8

Change in gravitational potential energy (Joules)=

Answer 8

Mass x gravitational field strength x change in vertical height
^GPE = m x g x ^h

Question 9

Kinetic energy (Joules) =

Answer 9

1/2 x m x v^2

Question 10

Efficiency =

Answer 10

Useful energy transferred / total energy supplied

Question 11

Wave velocity =

State both equations

Answer 11

Wave velocity = frequency x wavelength

Wave velocity = distance / time

Question 12

What is the equation for force which includes momentum ?

Answer 12

Force = change in momentum / time 
F = (mv - mu) / t

Question 13

What is the equation for work done?

Answer 13

Work done = force x distance

Question 14

What is the equation for power? A measure of how quickly work done is being done

Answer 14

Power = work done / time

Question 15

What is the equation for work done (measured in joules) ?

Answer 15

E = F x d

Work done in Joules= force in N x distance moved in direction of force

Question 16

What is the equation for power in watts?

Answer 16

P = E/t 
Power = Energy transferred in joules / time

Question 17

What is the equation for energy transferred in joules?

Answer 17

E = Q x V

Energy transferred in joules = Charge in coulombs x potential difference in volts

Question 18

What is the equation for potential difference in volts?

Answer 18

V = I x R

Potential difference in volts = current in amps resistance in Ohms

Question 19

What is the equation for charge in coulombs (C)?

Answer 19

Q = I x t

Charge in coulombs = current in amps x time

Question 20

What is the equation (one out of 2) for power in watts, including potential difference in volts?

Answer 20

P = I x V

Power in watts = current in amps x potential difference in volts

Question 21

What is the equation (one out of 2) for power in watts,including resistance in ohms (measured with Greek letter Omega)?

Answer 21

P = I(squared) x R

Power in watts = current in amps (squared) x resistance in ohms

Question 22

What is the equation for density in kg/m(cubed) or g/cm(cubed)?

Answer 22

p (lower case Greek letter rho) = m / V

Density in kg/m(cubed) or g/cm(cubed) = mass in kg/ volume in m or cm (cubed)

Question 23

What is the equation for pressure in N/m(squared) or N/cm(squared)?

Answer 23

P = F/ A

Pressure in N/m or N/cm (squared) = Force in N / Area in m or cm (squared)

Question 24

What is the equation for Force in N, including spring constant and extension?

Answer 24

F = k x X

Force in N = spring constant (in N/m, N/cm or N/mm) x extension (in m, cm or mm)