Question

Elias serves a volleyball at a velocity of 16 m/s. The mass of the volleyball is 0.27 kg. What is the height of the volleyball above the gym floor when its total mechanical energy is 41.70 J? Round to the nearest tenth. m

Answer 1

Answer:

2,7m

Explanation:

Total mechanical energy is the sum of kinetic energy plus potential energy.

kinetic energy can be expressed like $K=\frac{m.v^{2} }{2}$ and potential energy like $U=m.g.h$ Where m is the mass, v is the velocity, g is the gravity on the earth surface (9,8m/s^2) and h is the height we want to know, so:

Total mechanical energy =  $K=\frac{m.v^{2} }{2}$ + $U=m.g.h$

But Total mechanical energy = 41,71J = 41,71 kg.m^2/s^2

rearranging: $h=\frac{E-(\frac{mv^{2} }{2} )}{m.g}$

replacing: $h=\frac{41.70J-(\frac{0,27kgx(16m/s)^{2} }{2}) }{0.27kgx9.8m/s^{2} } = 2,7m$