Equations

Question 1

Weight

Answer 1

weight = mass x gravitational field strength

Question 2

Work done

Answer 2

Work done = force x distance (along the line of action from the force)

Question 3

Force applied to spring

Answer 3

Force applied to spring = spring constant x extension

Question 4

Moment of a force

Answer 4

moment of a force = force x distance (normal to direction of force)

Question 5

Pressure

Answer 5

Pressure = force / area

Question 6

Distance travelled

Answer 6

Distance travelled = speed x time

Question 7

Acceleration

Answer 7

Acceleration = change in velocity / time

Question 8

Resultant force

Answer 8

Resultant force = mass x acceleration

Question 9

Momentum

Answer 9

Momentum = mass x velocity

Question 10

Kinetic energy

Answer 10

Kinetic energy = 0.5 x mass x (speed)²

Question 11

Gravitational potential energy

Answer 11

Gravitational potential energy = mass x gravitational field strength x height

Question 12

Power

Answer 12

Power = energy transferred / time
or
Power = work done / time

Question 13

Efficiency

Answer 13

Efficiency = Useful output of energy / total energy input

Question 14

Wavespeed

Answer 14

Wave speed = frequency x wavelength

Question 15

Charge flow

Answer 15

Charge flow = current x time

Question 16

Potential difference

Answer 16

Potential difference = current x resistance

Question 17

Power (current)

Answer 17

Power = potential difference x current
or
Power = (current)² x resistance

Question 18

Density

Answer 18

Density = mass / volume