Question

A particle is moving with a constant speed along a straight line path. A force is not required to:

• A. Increase its speed
• B. Decrease its momentum
• C. Change the direction
• D. Keep it moving with uniform speed

Answer 1

The correct option is D Keep it moving with uniform speed

• Newton's first law states that, if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force. This postulate is known as the law of inertia.
• Hence a force is not required to keep the particle moving with uniform speed.