Physics Questions Help

If both of them have the same kinetic energy, let call the amount K, then the elephant have to go at a slow speed to reach K since it have a large mass. The mouse have to go at a fast speed to reach K since it have a small mass. So the mouse would have the faster speed.

3.On earth. Potential energy is mgh, where m=mass, g=gravity on earth, h=height. Since the gravity on the moon is only 1/6 the gravity on earth, the equation for potential energy on the moon is m(1/6)gh. If m and h stay constant, then the potential energy would change more on earth.

4. Potential energy=mgh; where mg = 1000N
Potential energy=1000(5)=5000J
Assuming all the potential energy transform in kinetic energy, then:
Kinetic energy is the same as potential.
The speed is:
mgh=(1/2)mv^2
gh=(1/2)v^2 (m cancel out on each side)
v=sqrt(2gh)=squareroot(2(9.8)(5))

5. Let U be the potential energy at the rooftop, so U=(1/2)mv^2.
If it fell from a roof that was four times higher, then 4U=(1/2)mv^2, so the kinetic energy is 4 times greater.
The speed for the first one is v=sqrt((2U)/m)
The speed of the second is v=sqrt((8U)/m), so if you compare these two speed by using sqrt(8)/sqrt(2), the speed of impact for the second one is twice the original.