A Ball is launched horizontally from a height of 3.2 m and strikes the ground 4.1 meters away (measured horizontally). What was the initial velocity of the ball? Would a stopwatch be a

reasonable device for measuring the time this takes? Why or why not?

u = 7.91 m/s

Explanation:

It is given that,

Height from which a ball is launched is 3.2 m

It strikes the ground 4.1 meters away

We need to find the initial velocity of the ball. When the ball strikes the ground, its final velocity is equal to 0. Let u is the initial velocity. Using the conservation of energy as follows :

Hence, the initial velocity of the ball is 7.91 m/s. Yes, a stopwatch be a  reasonable device for measuring the time this takes.

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray