Atwood Machine

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  • Atwood Machine
Model : 4003

The Atwood machine is often used to demonstrate the effects of gravity and the relationship between masses and acceleration. The setup allows for the examination of how the masses move and how their acceleration is affected by the difference in their values.

When the masses are unequal, the heavier mass will accelerate downward, while the lighter mass accelerates upward. The direction of the acceleration depends on which mass is heavier. The acceleration of the system can be calculated using Newton's second law of motion.

The equation for the acceleration (a) of the Atwood machine can be derived as follows:

a = (m2 - m1)g / (m1 + m2)


  • m1 is the mass on one side of the pulley
  • m2 is the mass on the other side of the pulley
  • g is the acceleration due to gravity (approximately 9.8 m/s² on Earth)

By measuring the acceleration, one can determine the difference in masses or vice versa. The Atwood machine provides a straightforward way to understand and apply Newton's laws of motion and the principles of equilibrium, acceleration, and the effects of gravitational force on objects of different masses.

Consists of two low-friction pulleys of 50 mm dia. mounted on a metal rod. Supplied complete with Support rod & base 5” x 8”, Slotted weight one each of 20g, 50g & 3 of 100g, 2 pcs. Mass hanger, 1 bosshead and nylon thread.

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