# Homework Help: Please check my solutions on the following scans.

1. Dec 15, 2008

### monkey13330gg

I'm sure that I have all the answers right except for number 5 and number 10.
http://i68.photobucket.com/albums/i15/monkey13330gg/scan0001.jpg
http://i68.photobucket.com/albums/i15/monkey13330gg/scan0002.jpg

On number 5, I think the answer is either B or E.

I think it is B because if the cart is already in motion when the timer starts, then the graph would start on the y-axis instead of all the way over to the right.

I also think that the answer is E because the distance between the graph and the y-axis indicate the friction that the force have to overcome to be able to make the cart go.

For number 10.

Somehow my answer does not seem right. I have E as an answer because the only thing I could get out of that graph is acceleration.

Please check on these two problems (number 5 and 10) and do any problem that you are interested in. Thank you very much.

2. Dec 15, 2008

### cepheid

Staff Emeritus
I'm only gonna look at 5 and 10.

For number 5, it means that there is zero acceleration for a non-zero force. I'll leave it up to you to determine what answer choice that leads to.

Hint: In the formula F = ma, F is the NET force acting on an object.

3. Dec 15, 2008

### cepheid

Staff Emeritus
10 looks good. Understand why:

It's not A because distance covered would be the area underneath each curve (clearly not the same for I and II)

It's not B because the inertial mass is the 'm' in F = ma, and although the two objects appear to have roughly the same acceleration, suggesting that there is a constant force acting on each one, that does not necessitate them having the same mass. It could be that they have different masses and are being acted upon by two *different* forces (eliminating D as well). These two different forces could differ by just the right amount in order to have the two objects of differing mass accelerate at the same rate.

It's not C because gravity is not relevant to the problem.

4. Dec 15, 2008

Thank you!