If the net force on an object is zero and the object is moving with a constant velocity, what is its acceleration?

If the net force on an object is zero and the object is moving with a constant velocity, what is its acceleration?

• A. 0 m/s^2
• B. Equal to velocity
• C. Equal to mass
• D. Equal to net force divided by velocity

Answer: (A)

Acceleration is the rate at which velocity changes. If the velocity is constant, there’s no change in velocity, so the acceleration is zero. This matches Newton’s second law: F_net = m a. If the net force is zero, then a = F_net/m = 0, meaning no change in motion even though the object could be moving. The object can have nonzero velocity today and still have zero acceleration tomorrow since there’s no unbalanced force to speed it up, slow it down, or change its direction.

Acceleration is the rate at which velocity changes. If the velocity is constant, there’s no change in velocity, so the acceleration is zero. This matches Newton’s second law: F_net = m a. If the net force is zero, then a = F_net/m = 0, meaning no change in motion even though the object could be moving. The object can have nonzero velocity today and still have zero acceleration tomorrow since there’s no unbalanced force to speed it up, slow it down, or change its direction.