Answer:
Searching in google I found the total mass and the radius of the ball (m = 1.5 kg and r = 10 cm) which are needed to solve the problem!
The ball rotates 6.78 revolutions.
Step-by-step explanation:
Searching in google I found the total mass and the radius of the ball (m = 1.5 kg and r = 10 cm) which are needed to solve the problem!
At the bottom the ball has the following angular speed:

Now, we need to find the distance traveled by the ball (L) by using θ=28° and h(height) = 2 m:
To find the revolutions we need the time, which can be found using the following equation:
(1)
So first, we need to find the acceleration:
(2)
By entering equation (2) into (1) we have:

Since it starts from rest (v₀ = 0):

Finally, we can find the revolutions:

Therefore, the ball rotates 6.78 revolutions.
I hope it helps you!