An unhappy individual is trying to slide a 100 kg desk across a wood floor. He pushes with a force of 800 N but the desk does not move. One can conclude that the force of friction (relative to the applied force of 800 N) is:kg m/s2 is a valid unit for what measurement?

When a body is in motion, it has resistance because the body interacts with its surroundings. This resistance is a force of friction. Friction opposes relative motion between systems in contact but also allows us to move, a concept that becomes obvious if you try to walk on ice. Friction is a common yet complex force, and its behavior still not completely understood. Still, it is possible to understand the circumstances in which it behaves

c) up is the direction the magnetic force is acting on the charge.