Physics Library / Computational resource
Pulleys and Atwood machines
Move the masses. Compare equal travel over a fixed pulley with the two-to-one motion of a movable pulley.
Fixed pulley
The 5 kg mass descends; both masses move the same distance.
One inextensible ropem1m2
Motion begins from rest. The display stops before a mass reaches the pulley or floor.
One rope, two coordinates
The fixed rope length makes one side rise exactly as far as the other falls.
m1, down positivem2, down positive
m2 acceleration2.45 m/s2
Rope tension36.79 N
m1 displacement0.00 m
m2 displacement0.00 m
Constraint residual0.000 m
T - m1g = m1a m2g - T = m2a