There are missing data in the text of the problem (found them on internet):
- speed of the car at the top of the hill:

- radius of the hill:

Solution:
(a) The car is moving by circular motion. There are two forces acting on the car: the weight of the car

(downwards) and the normal force N exerted by the road (upwards). The resultant of these two forces is equal to the centripetal force,

, so we can write:

(1)
By rearranging the equation and substituting the numbers, we find N:

(b) The problem is exactly identical to step (a), but this time we have to use the mass of the driver instead of the mass of the car. Therefore, we find:

(c) To find the car speed at which the normal force is zero, we can just require N=0 in eq.(1). and the equation becomes:

from which we find
Answer:
The mechanical energy is converted to potential energy while the kinetic energy is zero
Explanation:
mechanical energy is the sum of potential energy and kinetic energy. It is the energy associated with the motion and position of an object. The total mechanical energy is the sum of these two forms of energy.
The Law of Conservation of Energy: Energy cannot be created or destroyed, but is merely changed from one form into another. This means that potential energy can become kinetic energy, or vice versa, but energy cannot “disappear”.
The mechanical energy is converted to potential energy while the kinetic energy is zero
There are usually multiple methods for organizing items and information in a scientific investigation.
Answer:
1) the capacitance of the capacitor increases. This is due to the induction of opposite charges on the two surfaces of the dielectric by the plate, this increased the charge in the field, from C =Q/v, it is seen that capacitance C will increase with increase in Q since v is constant.
2) the electric field intensity will also increase with increase in electric charges provided plate separation d remains constant.