A 50.0 g toy car is released from rest on a frictionless track with a vertical loop of radius R (loop-the-loop). The initial height of the car is h = 4.00R.
a. What is the speed of the car at the top of the vertical loop?
b. What is the magnitude of the normal force acting on the car at the top of the vertical loop?

the speed of the car at the top of the vertical loop  

the magnitude of the normal force acting on the car at the top of the vertical loop  

Explanation:

Using the law of conservation of energy ;

The  magnitude of the normal force acting on the car at the top of the vertical loop can be calculated as:

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2

because if the tool that you are using is not balanced it there would be false mass.