A pendulum on some moon has a length of 1.5meters and a period of

[TutorGirl22]

A pendulum on some moon has a length of 1.5meters and a period of 4.2seconds. On Earth a girl throws a rock 13meters in the air, if she was on that moon how high would that same rock go if she threw it with the same effect? (Ignore all air resistance)

 

[rollcast]

T=2\pi\sqrt{\frac{L}{g}}

g=\frac{4\pi^{2}L}{T^{2}}

g=\frac{4\pi^{2}1.5}{4.2^{2}}

g= 3.3570083m/s²

Does that help you a bit?

 

[TutorGirl22]

I found the gravity okay, it was the next part that I got hung up on.

 

[rollcast]

Can you work out the initial velocity for the rock on the earth?

 

[TutorGirl22]

That's the train of thought that I had, but I don't know how I would do that.

 

[rollcast]

Think of the SUVAT equations, you know,

S = 13m
U = ?
V = 0 as at the maximum height the velocity will be zero
A = g for Earth


T doesn't matter

Which SUVAT equation has those 4 variables in it - SUVA ?