Hi there!
We can use the work-energy theorem to solve.
Recall that:
The initial kinetic energy is 0 J because the crate begins from rest, so we can plug in the given values for mass and final velocity:
Now, we can define work:
Now, plug in the values:
Solve for theta:
Correct order, from lowest potential energy to highest potential energy:
E - C - D - B - A
Explanation:
The gravitational potential energy of the car is given by:
where
m is the car's mass
g is the gravitational acceleration
h is the height of the car relative to the ground
In the formula, we see that m and g are constant, so the potential energy of the car depends only on its height above the ground, h. The higher the car from the ground, the larger its potential energy. Therefore, the position with least potential energy will be E, since the height is the minimum. Then, C will have more potential energy, because the car is at higher position, and so on: the position with greatest potential energy is A, because the height of the car is maximum.