phy 121
On problem #2 i'm not sure how to get started.
If we know the time down the incline and the length of the incline, we can immediately find the average velocity on the incline.
If initial velocity is zero and we have the average velocity we can find the change in velocity.
If we know the change in velocity and the change in clock time we can find the acceleration.
This is what you need to do for every trial. You are given the time required for each of three trials, and you are given the length of the incline. So you can find the acceleration for each trial.
If a cart accelerates uniformly down an incline 78 cm long in 2.7 seconds, then we know that v0 = 0, `ds = 78 cm and `dt = 2.7 seconds. We could use the equations of motion to find a.