# Homework Help: Forces and Systems Lab- Relationship questions

1. Oct 15, 2007

### xkaibob

I have a lab report due tomorrow on forces. Basically, we were supposed to calculate the kinetic friction of a "frictionless" system on a level place, an incline plane accelerating upwards, and an incline plane accelerating downwards.

I solved for mk by using the equation m(at + aA)= T-(mk)mg. I also calculated for tension and acceleration.

*Please note that the first m stands for mass of the sled, the (mk) means the kinetic frictional force, and the final m is the mass of the weight attatched.

This is my data thus far:

Experimental Results:

Level:
Acceleration: 4.89
Tension: .72
mk: .059

Downward Incline:
Acceleration: 6.642
Tension: .9798
mk: .087

Upward Incline:
Acceleration: 3.078
Tension: .454
mk: .039

Theoretical Results:

Level:
Acceleration: 4.038
Tension: .596
mk: .047

Downward Incline:
Acceleration: 5.885
Tension: .868
mk: .078

Upward Incline:
Acceleration: 3.478
Tension: .513
mk: .045

I've made the observation that the greater the acceleration, the greater the frictional force opposing the motion of the object.

Is that correct or am I missing something? And what am I supposed to incorporate the percent error of the frictional force for?

Thanks for any help. :]

Last edited: Oct 15, 2007