Question

if an object is travelling in a circle, which of the following must be true? choose all that apply. the object has a constant velocity. the object has a net force acting on it. the object is slowing down. the object is accelerating. the object is speeding up.

Explanation:

• Velocity is a vector (has magnitude and direction). In circular motion, direction of velocity changes (even if speed is constant), so velocity is not constant.
• For an object to move in a circle, there must be a centripetal force (net force towards the center of the circle) according to Newton's second law \(F = ma\).
• Circular motion doesn't imply speeding - up or slowing - down (uniform circular motion has constant speed). But since velocity direction changes, there is acceleration (centripetal acceleration \(a=\frac{v^{2}}{r}\), where \(v\) is speed and \(r\) is radius of the circle).

Answer:

• The object has a net force acting on it.
• The object is accelerating.