Centripetal force (HIGHER)

• What is centripetal force?

  Centripetal force is the force that keeps an object moving in a circular path. It acts towards the center of the circle and is required to maintain the object's acceleration towards the center.
• Why does an object moving in a circular orbit have a constantly changing velocity?

  When an object moves in a circle at a constant speed, its direction constantly changes. A change in direction causes a change in velocity. This is because velocity is a vector quantity – it has an associated direction as well as a magnitude. 
• Why is an object moving in a circular orbit at constant speed described as constantly accelerating?

  Acceleration is a change in velocity, either in its magnitude —i.e., speed — or in its direction, or both. In uniform circular motion, the direction of the velocity changes constantly, so there is always an associated acceleration, even though the speed might be constant.
• What is inertial mass?

  The measure of an object's resistance to changes in its motion.