# Cow jumps over the moon

diverse
A. How much energy must a 450.Kg cow expend in jumping over the moon?(excluding the moon's gravity and the earths atmosphere),

B. Assuming all the work is done during the jump itself, what would her initial velocity have to be?

C. What would her final velocity be upon her return to Earth?

D. Again assuming all the work would be done during the initial jump, i.e. for a distance approximately the length of her legs ( 1 meter ), what would her acceleration need to be.

## Homework Equations

EL = G Me m(1/r0 - 1/r1)

## The Attempt at a Solution

Substituting values in:
G = 6.67 x 10^-11 Nm^2 / kg^2
Me = 5.98 x 10^24 kg
m = 450. kg
r0 = 6.38 x 10^6 m
r1 = 3.85 x 10^8 m

Using all those in the big equation I get this:
2.77 x 10^10 J This would be her kinetic energy for A hopefully.

For part B I just used KE = 1/2 mv^2
Substituting everything in and solving for V I get 5550 m/s

I don't quite get question C, how would she even return to earth with that velocity?

For part D I haven't quite worked it out yet but I'am going to use
v^2 = V0^2 + 2a Delta t and just solve for the acceleration. But this assumes my velocity is right, which i'am not sure of.

Have I missed anything important in my thinking here? I can't really check my answers for reasonability

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