Posted by Lissa. on .
A 500 g block lies on a horizontal tabletop. The coefficient of kinetic friction between the block and the surface is 0.25. The block is connected by a massless string to the second block with a mass of 300 g. The string passes over a light frictionless pulley as shown above. The system is released from rest.
Start with a free-body diagram (FBD).
It solves most statics problems automatically when you isolate the system into individual pieces.
Start with the 500g block, mass m1.
coefficient of friction, μk=0.25
Frictional force = μkm1g
Let tension in string, T
Acceleration, a = (T-μkmg)/m
For the block at the other end of the string.
Net vertical force
Since two accelerations must be equal, we have
T/m1-μkg) = g-T/m2
Solve for t and substitute into formulas above to get a, acceleration.
You should get acceleration, a=2.1 m/s² approximately.