Initial State: An 8-month old child is at rest at the bottom of a staircase. Final State: The 8-month old child is at rest at the top of the staircase. Notes: The system includes the child and earth. The child uses the steps to slowly crawl up the staircase

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 ?

For which pair of objects would adding the same a

Two carts, one of mass 2m and one of mass m, approach each other with the same speed, v. when the carts collide, they hook together. assume that positive momentum is to the right. which graph best represents the momentum of both carts over time, before and after the collision?