Why do we say that objects moving in a circle have acceleration even if their speed remains constant?
Because their speed might remain constant, but their velocity doesn't. Remember, velocity is a vector, so it has magnitude (which is the speed of the object), but also direction. For an object moving in a circle (or along any curve, for that matter), the direction of the velocity is constantly changing. This change in the velocity vector is explained by an acceleration pointing towards the centre of the circle called centripetal acceleration.
BA
Related Physics GCSE answers
All answers ▸Why do we use non-renewable energy?
How to find wave speed from frequency and wave length.
When a force is applied to a spring, the spring extends by 12cm. The spring has a spring constant of 25 N/m. Calculate the force applied to the string in N.
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)