Exploring Pulleys

There are several different ways to use a pulley to lift an object. Some ways the scale will read the weight of the object (or object plus pulley), but other ways the scale reading will be significantly more or less. For each case shown, predict what you think the scale reading will be, and click on a button to record your prediction.

In these drawings, the circle is a wheel that is free to turn; the line to the center of the wheel is a rope that holds the center in place (or causes it to move); the two lines that go to the edge of the wheel are the two ends of the same rope (blue, in the diagram to the right).

Scale reading will be Less Actual Weight More	Scale reading will be Less Actual Weight More
Scale reading will be Less Actual Weight More	Scale reading will be Less Actual Weight More

Now make each system and check your predictions. For each one, also observe how far you have to pull up on the string to which the scale is attached to cause the object to rise 2 cm: is this also 2 cm, or is it significantly more or less?

Check the box when you are done:   

Science content: simple machines