Is it possible to have motion in the absence of a force? Explain.?

Answer 1

Sure. It's called "inertia". An object in motion *continues* to remain in motion less acted upon by a force.

Answer 2

Sure you can. Assume a mass m in motion with velocity v. If p = mv, which is the momentum of that mass, a change in momentum over time is dp/dt = d(mv)/dt = m dv/dt for non relativistic conditions and/or a fixed mass.

We assumed that v = constant; so that p = mv remains the same over time. This means that dp/dt = m dv/dt = 0 and that results because the change in velocity is dv/dt = 0 since we started by saying the mass was moving at a constant velocity.

But look at this...dp/dt = 0 = m dv/dt = m a = force because a mass accelerates only when a net force acts on it. That is f/m = a. But our assumption was that dv/dt = 0 = a; so that f/m = a = 0 so f = 0 since mass is > 0; or, ta da, there is "an absence of a force" on the mass moving at velocity v = constant .

In other words, according the Newton's first law of motion, a body at constant velocity will stay at constant velocity unless a net force is applied to it (to change the velocity over time).

Answer 3

F = m*a.

It is not possible for an object to go from a motionless state to a state in motion without a force. But, a body may be in motion w/o the continued application of that force. That body my also stay in motion indefinitely if the environment is frictionless.