Hi there!
The answer would be B. the slope of the plane.
Changing the slope of the plane would show how fast the ball went when Galileo changed the steepness of the slope. If he didn’t change the slopes steepness he would have the same results each time.
Hope this helps !
Answer:
Part a)

Part B)

Part C)

Explanation:
Part A)
As we know that ball is hanging from the top and its angle with the vertical is 20 degree
so we will have






Part B)
Here we can use energy theorem to find the distance that it will move




Part C)
At terminal speed condition we know that




Answer:
The handrails must be approximately 10.63 meters long
Explanation:
The given parameters are;
The height of the bleachers, h = 8 m
The depth of the bleachers, d = 7 m
The length of the hand rails to go along the bleachers from bottom to top is given by Pythagoras' Theorem as follows;
The length of the hand rail = √(d² + h²)
∴ The length of the hand rail = √(7² + 8²) = √113 ≈ 10.63
In order for the handrails to go along the bleachers from top to bottom, they must be approximately 10.63 meters long.
The answer is C. elastic potential energy