Physics problem?

Question

A common flea is recorded to have jumped as high as 21 cm. Assuming that the jump is entirely in the vertical direction and that air resistance is insignificant, calculate the time it takes the flea to reach a height of 7.0 cm. if this is the maximum height of the jump. Please show how you got the answer. I really need this tonight. Thanks!!!

Answer 1

1/2 mvo^2 = mg h ( energy balance) vo initial velocity
At maximum height kinetic energy is 0
vo= sqrt(2gh) = sqrt( 2*9.8 *0.07)= 1.17m/s
t for h max = vo/g = 0.12s