A Levels Physics

Three of these quantities have the same unit.
Which quantity has a different unit?
A
energy
distance
B force
C power x time
D rate of change of momentum


Choice C is correct because:

The unit of power is watt (W), and the unit of time is second (s). 

When power is multiplied by time, the resulting unit is watt-second (Ws), which is equivalent to joule (J), not newton (N).

Choice A is incorrect because:

The unit of energy is joule (J), and the unit of distance is meter (m). 

Dividing energy by distance gives us J/m, which is equivalent to newton (N) (same as others).

Choice B is incorrect because The unit of force is newton (N) (same as others).

Choice D is incorrect because:

The unit of momentum is kilogram meter per second (kg m/s). 

Dividing momentum by time gives us kg m/s per second (kg m/s²), which is equivalent to newton (N) (same as others).

SI Units and Significant Figures | 2012 - O/N - 9702/13 | Q4