A small object carrying a charge of -7.00 nC is acted upon by a downward force of 23.0 nN when placed at a certain point in an electric field. A. What are the magnitude and direction of the electric field at the point in question?
B. What would be the magnitude and direction of the force acting on a proton placed at this same point in the electric field?

Many machines- including inclined planes such as ramps- increase the strength of the force put into the machine but decrease the distance over which the force is applied. true or false

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.

Why is the energy that results from a roller coaster's position at the top of a hill referred to as potential energy?