A ball has a 17 J of kinetic energy and its mechanical energy ls 25 Joule.  a. Find the gravitational potential energy of the ball.

Question:

A ball has a 17 J of kinetic energy and lB mechanical energy is 25 Joule

a. Find the gravitational potential energy of the ball.  

b. if the ball has a mass of 3.2 kg, what is its height above the ground?  

c. What is the speed of the ball?

a.  = 85

b. h = 0.25 m

c. = 3.26 m/s

Explanation:

Part A

PEgrav = m ו g • h

In the above equation, m represents the mass of the object, h represents the height of the object and g represents the gravitational field strength (9.8 N/kg on Earth) - sometimes referred to as the acceleration of gravity. So, to find:

GPE = ME - KE = 25 - 17 = 85

Part B

The formula simplifies to: h max = h + V₀² / (2 × g) and the time of flight is the longest.

The vertical velocity is equal to 0 (Vy = 0), and that's the case of horizontal projectile motion.

The equation may be written as:

    GPE = mgh

    8 = 3.2 × 10 × h

    h = 0.25 m

Part C

The ball speed is calculated by dividing the distance by the time. If the time was 3 seconds, the average speed will be 60/3 = 20 feet per second (6.1 m/sec). KE = 1/2 MV²

            17 = 1/2 × 3.2 x V²

            V = 17 ÷ 1.6

Note, this is only the average ball speed, the speed of the ball at the time of release would be greater.