66 is the answerrrrrrr I thinkkkkk
The answer they are looking for is the last one. However the last two are technically correct but the third one would result in negative work.
Answer:
100 J
Explanation:
The potential energy is given by the formula ...
PE = mgh
= (2 kg)(10 m/s^2)(5 m) = 100 J
Answer:
a) 
b) 
Explanation:
Part a
For this case we can begin finding the period like this:

Then we know that the centripetal acceleration is given by:

And the velocity is given by:

If we replace this into the acceleration we got:

And we can replace the values and we got:

Part b
For this case we want to find a value of k such that:

Where a = 9.74, so then we can solve for k like this:

The properties of the wave don't determine its speed. The properties of the medium do. You can FIND the speed by measuring the wave's frequency and wavelength.