Calculating G Using an Inclined Track

1. Oct 2, 2011

jpm_iv

I need to experimentally find gravity using information from a lab we finished last week. Should I not be getting 9.8 m/s² at each angle or am I doing something wrong? And if I should indeed be getting ≈9.8 m/s² as my y-acceleration, can you point me in the right direction?

2. Oct 2, 2011

grzz

You can get more help if you give a diagram of the apparatus used and the measurements taken.

3. Oct 2, 2011

jpm_iv

Sorry for being unspecific, I was looking more for a general answer. But we had a cart travel down a sloped track, had times recorded at A and B, along with a time taken to travel from A to B, all of which were known distances. This was used to calculate v1, v2, and a. Then we had taken two height measurements 60cm apart, and used this to find the angle of the track to the table. Then I multiplied the calculated acceleration by sine of the angle to get y-acceleration. Basically should this y-acceleration be ≈9.8 m/s/s or should it be proportionally related like y-acceleration/angle = g/90?

4. Oct 2, 2011

grzz

Were there any other forces parallel to the track besides a component of the weight of the cart?

5. Oct 2, 2011

jpm_iv

Nothing was applied to the cart directly, it was just set at the top and then released. Obviously there are factors of friction and air resistance, but this is the third week of a high school mechanics course and we're limiting everything to kinematics.

6. Oct 2, 2011

grzz

If friction is negligible (eg air track) then the measured acc will be gsin(angle between track and horizontal)

7. Oct 2, 2011

jpm_iv

Okay, that gives me more consistent results. I had been solving for g by g=asin.