Atwood machine with 0.5 kg and 0.4 kg masses

Answer: acceleration = 1.09 m/s² (rope tension 4.359 N).

What we know

  • Mass 1 (heavier side): 0.5 kg
  • Mass 2 (lighter side): 0.4 kg

Step by step

Given
m₁ = 0.5 kg, m₂ = 0.4 kg
Formula
a = (m₁ − m₂)g / (m₁ + m₂)
Substitute
a = (0.5 − 0.4) × 9.80665 / (0.5 + 0.4)
Result
a = 1.09 m/s²

All results

Acceleration1.09 m/s²
Rope tension4.359 N

Open the atwood machine calculator with these numbers → and change any of them.

The physics

An Atwood machine is two masses connected by a rope over a single pulley — the classic teaching rig for Newton's laws. The heavier mass falls, the lighter one rises, and both share the same magnitude of acceleration because the rope is inextensible.

Standard acceleration of gravity →