# AP Physics Summer work problems!

1. Aug 22, 2008

1. The problem statement, all variables and given/known data

Assuming you have a bow that behaves like a spring with a spring constant of 168 N/m and you pull it to a draw of 54 cm, to the nearest joule how much work do you perform?

2. Relevant equations

The force of a constant spring is f=-k(x) where x is the displacement and k is the spring constant.

3. The attempt at a solution

So Basically If I find the force and then place it into the simple work equation W=F(x) where x is displacement and F is force. I get 49(rounded). Am I doing this correctly?

2. Aug 22, 2008

### chislam

There's an equation for potential spring energy... it looks similar to the kinetic energy equation, but with different variables.

3. Aug 22, 2008

### Topher925

Yes, it looks like you are doing it correctly to me. Basically, W = k*x^2 in this case.

Ok, but what does that have to do with this problem?

4. Aug 22, 2008

Is use that equation of u=1/2kx^2 and got 24.4944 joules. How does that convert to the work performed?

5. Aug 22, 2008

Another quick question! There is a second part which is... to the nearest tenth of a m/s, what is the speed of the 98 gram arrow when it is released?

I know I have to find the velocity but I have no clue how to do it.

I've never taken physics before and it's decenlty hard to teach yourself=/

6. Aug 22, 2008

### chislam

This link shall explain why you simply can't use W=kx^2, but instead W=.5kx^2