Fleas have remarkable ability to jump. A 0.40 mg flea, jumping straight up, would reach...

Given: 
mass, ${\displaystyle m=0.4mg=0.4\times {10}^{-6}kg}$ 
maximum height reached, h = 35 cm = 0.35 m 
Formula used: 
The kinetic energy is equal to
${\displaystyle K=0.5m{v}^2}$ 
The potential energy can be expressed as
${\displaystyle U=m\times g\times h}$ 
mass, ${\displaystyle m=0.4mg=0.4\times {10}^{-6}kg}$ 
maximum height reached, h = 35 cm = 0.35 m 
(a) Let K is the kientic enregy as it leave the ground. BY use of conservation of energy, the potential energy at teh top is equal to the kientic energy at the ground. 
The potential energy at the top, ${\displaystyle U=0.4\times {10}^{-6}\times 9.8\times 0.35=1.37\times {10}^{-6}J}$ 
So, the kinetic energy as it leaves the ground is ${\displaystyle 1.37\times {10}^{-6}J}$. 
(b) The potentai energy at the top is ${\displaystyle 1.37\times {10}^{-6}J}$.