Question

a vehicle of known mass accelerates along a straight path. what cased this acceleration, according to newtons second law of motion? the mass of the vehicle has changed. the direction of the vehicle has changed. a balanced force has acted on the vehicle. an unbalanced force has acted on the vehicle.

Explanation:

Newton's second law states that \(F = ma\) (force equals mass times acceleration). For an object to accelerate (\(a
eq0\)), there must be a net force (\(F_{net}
eq0\)). A net force implies an unbalanced force. If the mass is known (and not changing as per the problem statement), and the vehicle is accelerating (not moving at constant velocity or at rest), an unbalanced force must be acting. A balanced force (\(F_{net} = 0\)) would result in no acceleration (\(a = 0\)). The direction change (if applicable) is a result of acceleration, but the cause of acceleration is the unbalanced force. Since the mass is given as known (and no indication of it changing), the mass - change option is incorrect.

Answer:

An unbalanced force has acted on the vehicle.