A 1.8 kg book had been dropped from the top of the football stadium. It's speed is 4.8 m/s when it is 2.9 meters above the ground what is its mechanical energy?

72.936 Joule

Explanation:

Mechanical Energy = Potential Energy + Kinetic Energy

Kinetic Energy = (1/2) x m x V² = (1/2) x 1.8 x 4.8² = 20.736 J

Potential Energy = m x g x h = 1.8 x 10 x 2.9 = 52.2 J

Total Mechanical Energy = 20.736 + 52.2 = 72.936 Joule