When a bus is moving (especially with a high speed) on the road suddenly stops or suddenly changes its direction, the luggage on the top due to inertia of motion and direction continues to remain in the motion or in the same direction of motion. As a result, the luggage may get thrown out from the bus roof ---is an example of which law of motion?

I believe its Newtons first law.

Explanation:

His first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. ... The amount of the change in velocity is determined by Newton's second law of motion.

a charge 3q is at the origin, and a charge −2q is on the positive x axis at x=a. part a where on the x-axis would you place a third charge so it would experience no net electric force? enter an expression for the exact answer, which will involve a square-root sign. (do not enter an approximate decimal answer.)