Q1. A student who weighs 510 N is wearing a backpack that weighs 70 N. The student is standing still on a level ground. Give the answers to the following questions in Newtons.
(a) What is the magnitude of the net force on student?
(b) What is the magnitude of the contact force on the student by backpack?
(c) What is the magnitude of the contact force on the student by ground?
Q2. A proton is initially at rest at a point where the potential is 459 V. Sometime later the proton is at a point where the potential is 218 V. If no force other than an electrostatic force acts on the proton, what is its final kinetic energy?