Which change decreases the resistance of a piece of copper wire

Crowbar of 5 metre is used to lift an object of 800 metre if the effort arm is 200cm calculate the force applied

The free body diagram shows a box being pulled to the left up a 25-degree incline. the magnitude of the normal force is

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.