Question

Starting from rest, a 2.1x10-4 kg flea springs straight upward. While the flea is pushing off from the ground, the ground exerts an average upward force of 0.41 N on it. This force does 3.7x10-4 J of work on the flea. (a) What is the flea's speed when it leaves the ground? (b) How far upward does the flea move while it is pushing off? Ignore both air resistance and the flea's weight.

Answer 1

1.327363 m/s

0.00090243 m

Step-by-step explanation:

u = Initial velocity

v = Final velocity

m = Mass of flea

Energy

`E=(1)/(2)m(v^2-u^2)\\\Rightarrow 3.7* 10^(-4)=2.1* 10^(-4)(v^2-0)\\\Rightarrow v=\sqrt{(3.7* 10^(-4))/(2.1* 10^(-4))}\\\Rightarrow v=1.32736\ m/s`

The velocity of the flea when leaving the ground is 1.327363 m/s

`W=F* s\\\Rightarrow s=(W)/(F)\\\Rightarrow s=(3.7* 10^(-4))/(0.41)\\\Rightarrow s=0.00090243\ m`

The flea will travel 0.00090243 m upward