- #1
kspabo
- 19
- 0
Homework Statement
Boxes are placed on a slope at uniform intervals of time trelease and slide down the slope with uniform acceleration. Knowing that as a box B is released, the preceding box A has slid 6 meters down the slope and that 1 second later they are 10 meters apart, determine the following:
(a) The value of trelease
(b) The acceleration of the boxes.
Homework Equations
ΔV = a⋅Δt
Δx=Vi⋅t+½⋅a⋅t2
2⋅a⋅Δx=Vf2-Vi2
The Attempt at a Solution
This problem isn't actually homework, I'm just studying. I'm posting the solution to the problem because I simply don't understand how exactly they arrive at the equations that they do. Here it is:
http://i.imgur.com/oSyIFsm.png
For example, equation (2) doesn't make sense to me as t = tr + 1, yet in the problem t = 1. Also, how come in eqn. (3) they don't employ the 10 m @ t=tr+1? Why is Δx simply xA@tr+1?