Question

What is needed in order to cause an object at rest to move, or an object in motion to change direction or speed?

Answer 1

an outside force, since according to newton's first law, an object at motion will remain in motion an object at rest will remain at rest, unless an outside force acts on it (Inertia is the resistance to change, but the change in direction requires an outside force)

Answer 2

i think its Inertia.. hope this helped