Question

# why do objects move in space with constant velocity even if we put force on it...

why do objects move in space with constant velocity even if we put force on it and it us not the same on earth

Soln:

From Newton's Law,it is clear that force is change of momentum(momentum=mv) of a body.If we applied a force on an object for some time that means we changed its momentum.On Earth an object in motion will stop due to air drag or friction,which is actually a force that is acting opposite to the force.This air drag or friction will stop the body from moving.The object in motion has two components that can be changed mass(m) and velocity(v).But in the case of an object in space there is no force(no friction) that will stop the body from moving and it will maintain its constant velocity.An external force is required to accelerate any object in the universe.If a body is given an initial acceleration continues to travel with uniform velocityafter the withdrawal of force in space unless it enters the gravitational field or come across the heavenly body.