Answer:
Explanation:
Here the total force at the horizontal components will be equal to the centripetal force on the car. So we will have:
(1)
- f(fr) is the friction force
- N is the normal force
Now, the sum of forces at the vertical direction is equal to 0.
(2)
Let's combine (1) and (2) to find f(fr)

I hope it helps you!
Explain or message me what your trying to ask!
The amount of gravitational potential energy acquired by the rock is equal to:

where
m is the mass of the rock
g is the gravitational acceleration

is the increase in height of the rock
Substituting the data of the problem, we find

So, Natalie gave 220.7 J of energy to the rock.