I wanted to point out that F = - 3/2 m1 a1 is in agreement with W = 3/2(KE)
The proof:
W = ΔKE1 + ΔKE2
ΔKE1 = (1/2m1v1f2 - 1/2m1vo12) = 1/2m1v1f2
ΔKE2 = (1/2m2v2f2 - 1/2m2vo22) = 1/2m2v2f2
W = 1/2m1v1f2 + 1/2m2v2f2
m2 = 2m1 and v1 = (1/2)v2
W = 1/2m1v1f2 +...
I think I figured out a good way of conceptually looking at this problem. The energy that is contained in the push has to do 2 things. It has to get platform 1 moving and it has to get platform 2 moving. So the energy that is contained in the push is divided in half. The the energy that is...
Thank you ehild! My question was pretty much why I couldn't use mechanical advantage to solve the problem, and as you pointed out you can only use mechanical advantage when there is zero acceleration.
Homework Statement
Two masses hang by a pulley system shown in the attachment. The masses both weigh the same. Find the tension on the rope.
The first attachment is straight from the book, the second attachment is me redrawing it with labels along with a free body diagram of each mass...
I'm still a little confused. What is seems like you are doing is you are adding the change kinetic energies of both objects (or other wise the work done to both of them). But when I do so, I get a different solution than the one you show.
Here is how I do it:
So the work done on the...
Hello paisiello2 and thank you for your reply. The work in this problem I think isn't supplied by gravity but the push the engineer provides. So work indeed has been done to platform 1 to get it moving, but it was done for a brief period of time. According to Newton's 2nd law, forces make...
Hello BvU and thank you for your reply/kind words! How is the work with the push 2m1Δv1?
This is how I figured out the work done by the push from the engineer would be:
W = ΔKE + ΔPE
W = [(1/2)m1v1f2 - (1/2)m1v1o2] + (m1gh1f - m1gh1o)
Setting the initial velocity as the velocity...
Hello, I am new. I hope that this is the correct place for this kind of question. I apologize for it being so long or annoying.
Homework Statement
An engineer that has a mass of 100kg has made an ideal mechanical advantage machine shown in the attachment. Platforms 1 and 2 are...