What is the difference between speed and velocity?

The difference is a bit subtle. Velocity is speed in a particular direction.

So, for example, a car travelling at 50 miles per hour round a bend is travelling at constant speed. Its direction is changing, however, so its velocity is also changing.

Velocity is always measured from a single point. So an object traveling in a circle has velocity zero relative to the centre of the circle, since the distance from the centre to the object is constant..

JK

Related Physics GCSE answers

All answers ▸

Explain why the velocity of a car moving at a constant speed around a bend changes.


A car of mass 1000 kg is travelling at 15 m/s. The driver applies the brakes for 4 seconds, slowing the car to 5 m/s. What is the average power output of the brakes over the 4 seconds? Assume there are no other forces acting on the car.


Explain why the stability of a car can be improved by widening the wheel base and lowering the centre of gravity.


Explain why an ice cube submerged in a drink melts faster than an ice cube on a kitchen surface (the drink, surface and room temperature are all equal). (3 marks)