Please answer everything!
13. As a car goes up a hill, there is a force of friction between the road and the tires rolling on the road. What is the force of friction equal to:
A. the normal force of the road times the coefficient of static friction.
B. the weight of the car times the coefficient of static friction
C. zero
D. the weight of the car times the coefficient of kinetic friction
E. the normal force of the road times the coefficient of kinetic friction
14. A and B are both points on an equipotential surface. What is the potential difference between point A and B?
A. To solve this, the electric potential of the equipotential surface must be known
B. It is zero
C. To solve this, the path taken from A to B must be known
D. To solve this, the electric potential at both A and B must be known