A 30 kg child climbs 15 meters up a tree. When he looks around, when is the child’s potential energy ?

The man of mass m1 and the woman of mass m2 are standing on opposite ends of the platform of mass m0 which moves with negligible friction and is initially at rest with s = 0. the man and woman begin to approach each other. derive an expression for the displacement s of the platform when the two meet in terms of the displacement x1 of the man relative to the platform.

If state law mandates that elevators cannot accelerate more than 2.40 m/s2 or travel faster than 14.8 m/s , what is the minimum time in which an elevator can travel the 373 m from the ground floor to the observatory floor? ?

You are standing on a boat. which of the following strategies will make the boat start moving? a. pushing the mast b. throwing some cargo out of the boat c. pushing the front ofthe boat d. pushing another passenger