According to Newton's Third Law, if someone jumps off a skateboard, the skateboard will roll backwards because

If someone jumps off a skateboard, the  skateboard will roll backwards because action and reaction are equal and opposite.

Newton's third law states that action and reaction are equal and opposite. That is, for every action there is a resulting reaction equal in magnitude to the action but opposite in direction.

If someone jumps off a skateboard, he will exert an action force downwards while the skate board exerts a reaction force upwards on him. This causes the skateboard to move backwards while he moves upwards.

Thus,  if someone jumps off a skateboard, the  skateboard will roll backwards because action and reaction are equal and opposite.

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the working equation for the angular size is the product of the physical size and 360 degrees divided by the product of two pi and distance from earth. the minimum size would be 0.559 degrees while the maximum size would be 0.49 degrees.