M.10(1) - SIMPLE LEVER

A metal base supports a ruler by its center allowing it to sway on its base. The ruler has two weight hangers that can be adjusted to any place on the ruler. The apparatus shows that the torque exerted by any force is equal to the force lever arm. A set of slotted weights is also provided.

M.10(2) - TORQUE DEMONSTRATION

A stepped wheel with different weights hanging at different radii maintains its equilibrium. The wheel is held by its center and is free to rotate. From each radius, there is a light string to hold the weights. It can be used to illustrate the basic relations between force and distance: requirements for equilibrium, how the same amount of work can be done with a lot of torque (the easy way) or with a little torque (the hard way); how a lever arm affects the force required to raise a weight.

M.10(3) - MAXWELL'S WHEEL - ROLLING SPOOL

A large spool has a string wrapped around its inner drum several times. Place the spool on the floor or on top of the table. First let the string come out on top as you pull it. It will move in your direction. Next, turn the spool over and pull the string in the same direction. The spool will still move forward.

Ask the students which way the spool will rotate when the srping is pulled horizontally. It may surprise them that the spool still rolls towards the demonstrator.

Finally, you can show that it will continue to do so until the angle is reached where the line of action passes through the point of contact of the spool and table. The spool will slip forward if the line of action of the pull passes through the point of contact of the spool and the table.