Atwood's machine
, also translated as Atwood or Atwood, is an English pastor, mathematician and physicist George Atwood's "About Objects" published in 1784.
proposed in the article "Straight Motion and Rotation", a mechanism for measuring acceleration and verifying the laws of motion. This machine is now often used in school teaching to explain the principles of physics, especially mechanics.
Its basic structure is to suspend two masses of equal mass on both ends of a light rope that crosses a fixed pulley. When another small mass is attached to a mass, the mass will accelerate and slide down from a standstill. The add-on block automatically disengages, and the system moves at a constant speed. The acceleration of gravity can be obtained by measuring this movement speed. An ideal Atwood machine consists of two object masses m 1 and m 2 , and an ideal and weightless pulley connected by a weightless, inelastic rope. When m 1 = m 2 , the machine is in a state of force balance. When m 2 > m 1 , both objects are subject to the same constant acceleration.
Atwood machines can be used to prove Newton's second law.
If the weight difference between m 1 and m 2 is small, the moment of inertia ( I ) caused by the radius of the pulley ( r ) cannot be ignored.
The angular acceleration of the pulley can be obtained from the following formula:
In this case, the total moment of the system is:
