Atwood Machine
Specification:-

It is used to study the motion under the effect of gravity of two mass systems connected through a lightweight cord, one on either side of a simple pulley.
This apparatus comprises 2 long metals rods.
Complete set includes electromagnetic release arrangement, set of 2 pairs of masses, Loading One rod having a well-balanced 10cm pulley mounted at its one end on near-frictionless bearings and threads at other ends for attaching it to the second rod to get a total working length of 245cm. 
Masses 1g, 2g, table/ring brackets, wall mounting clamps and lightweight cord.
A scale 0- 245-1cm continues from the top of the rod with a pulley to the bottom of the second rod. 

Atwood Machine