Atwood's Machine

​
mass on the left in kg
1.9
mass on the right in kg
2.
time
acceleration:
0.3 m/
2
s
distance traveled:
1.50 m
time moving:
3.455 s
A simple demonstration of Newton's second law is provided by Atwood's machine, which consists of a pulley between two masses. The problem is to calculate the acceleration of the two masses. (Their magnitudes are equal but of opposite sign.) If the masses are equal, the system is in equilibrium and nothing moves.

Details

The acceleration of the left-hand mass is given by
a=
m
1
-
m
2
m
1
+
m
2
g
, where
m
1
and
m
2
are the left- and right-hand masses in kg and
g
is the acceleration due to gravity. It travels a distance
d
while the trigger is active (it is stopped when the || button is clicked). The quantities
a
and
d
are taken as positive when the left-hand mass moves upward and negative when it moves downward. The time during which the masses are moving before hitting bottom is given by
t=
2d/a
.

External Links

Pulley (ScienceWorld)
Acceleration (ScienceWorld)
Newton's Second Law (ScienceWorld)

Permanent Citation

Enrique Zeleny
​
​"Atwood's Machine"​
​http://demonstrations.wolfram.com/AtwoodsMachine/​
​Wolfram Demonstrations Project​
​Published: December 6, 2007