(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Two blocks with different mass are attached to either end of a light rope that passes over a light, frictionless pulley that is suspended from the ceiling. The masses are released from rest, and the more massive one starts to descend. After this block has descended a distance 1.30 , its speed is 1.00 .

If the total mass of the two blocks is 18.0 , what is the mass of the more massive block?

Take free fall acceleration to be 9.80 .

I set the heavier block as m1.

2. Relevant equations

m1gh1+0.5m1v1^2=m2gh2+0.5m2v2^2

3. The attempt at a solution

They both start at height 0 and velocity 0 and so the initial PE and KE is going to be 0, and so the initial Mechanical energy is also 0 (I'm pretty sure this is wrong but don't know how to fix it). Then m1 drops 1.30m so thats h1 and m2 goes up -1.30m=h2. v should be equal between both, m1=1, m2=-1.

m1(gh1+0.5v^2)=m2(gh2+0.5v^2)

m1/m2=(gh2+0.5v^2)/(gh1+0.5v^2)

=(9.8*-1.30+1/2*-1^2)/(9.8*1.30+1/2*1^2)

Therefore

m1=-m2

So its wrong ahah I was wondering if someone could help me?

Thanks in advance!:shy:

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Conservation Of Mechanical Energy

**Physics Forums | Science Articles, Homework Help, Discussion**