Aramp is often used to raise an object. if 80 joules of energy are needed to lift an object to a platform but 100 joules are used in rolling the object up the ramp, what percent of energy was wasted in the form of heat due to friction?

Write the equation for momentum, first using symbols for the variables, then using words for the variables.

Aforce of 9.00 newtons acts at an angle of 19.0 to the horizontal. what is its component in the horizontal direction?

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.