# Homework Help: 3 masses connected by a pulley

1. Sep 19, 2007

### sheri1987

1. The problem statement, all variables and given/known data

The three blocks shown are relased at t=0 from the position shown in the figure. Assume that there is no friction between the table and M2, and that the two pulleys are massless and frictionless. The masses are: M1 = 3.0 kg, M2 = 7.0 kg, M3 = 5.0 kg.

Calculate the speed of M2 at a time 1.35 s after the system is released from rest.

http://nplq1.phyast.pitt.edu/res/msu/physicslib/msuphysicslib/09_Force_and_Motion/graphics/prob81_pulley2

2. Relevant equations
I figure I need an equation with time like V= Vo +at and then I also need to use an equation to solve for a. I know all of the a's are equal (a1=a2=a3), yet I do not know which equation to use.

3. The attempt at a solution
for the first equation I plugged in V=Vo +at, t was the 1.35s, Vo = 0, v is unknown, and a I am unsure how to get still? Could you please help me out?

2. Sep 19, 2007

### learningphysics

Not able to see the picture.