13. momentum is an object’s mass times velocity. which has more momentum? a paper airplane with a mass of 10g flying at a velocity of 4m/s, or a real airplane that is parked on a runway with a mass of 1000kg and a velocity of 0m/s

Are aliens real? justify you’re answer.

The boy of mass 30 kg is at r1= 2 meters from the fulcrum. of the girl is 45 kg, at what r2 must she sit so that they are balanced ?

Question part points submissions used suppose that 2 j of work is needed to stretch a spring from its natural length of 26 cm to a length of 36 cm. (a) how much work is needed to stretch the spring from 28 cm to 32 cm? (round your answer to two decimal places.)