Mechanical Advantage and the Inclined Plane: More Practice

Levers and Torque: Student Learning Goal The student will be able to solve problems involving torque, force, load-arm length, and effort-arm length as they relate to levers (C2.5).

Levers and Torque SPH4C

The Lever A lever is a rigid bar that can rotate freely around a support called a fulcrum.

Torque When a force causes a rigid body to rotate, we say that a torque has been applied. Torque is defined as the turning effect.

Torque Torque ( T ) increases as force ( F ) increases and also increases as distance ( d ) from the fulcrum increases:

Torque Torque ( T ) increases as force ( F ) increases and also increases as distance ( d ) from the fulcrum increases:

Torque Torque ( T ) increases as force ( F ) increases and also increases as distance ( d ) from the fulcrum increases: Torque has units of N m.

Torque: Example A force of 84 N is used to turn a wrench of length 25 cm. What was the torque on the wrench?

Torque: Example A force of 84 N is used to turn a wrench of length 25 cm. What was the torque on the wrench?

Torque: Example A force of 84 N is used to turn a wrench of length 25 cm. What was the torque on the wrench?

Torque: Example A force of 84 N is used to turn a wrench of length 25 cm. What was the torque on the wrench?

Torque: Example A force of 84 N is used to turn a wrench of length 25 cm. What was the torque on the wrench?

Load torque and Effort torque For any lever there are two torques: the load torque ( T L ) and the effort torque ( T E ): d L and d E are referred to as the load arm and effort arm, respectively.

Static Equilibrium If the load torque equals the effort torque, the lever is in static equilibrium.

Static Equilibrium If the load torque equals the effort torque, the lever is in static equilibrium.

Static Equilibrium: Example What force does your bicep need to exert to hold a weight of 134 N (30 lbs)? Remember that the human forearm is a lever.

Static Equilibrium: Example What force does your bicep need to exert to hold a weight of 134 N (30 lbs)? We will ignore the weight of the forearm itself.

Static Equilibrium: Example What force does your bicep need to exert to hold a weight of 134 N (30 lbs)?

Static Equilibrium: Example What force does your bicep need to exert to hold a weight of 134 N (30 lbs)? Or approximately 800 N

More Practice Levers and Torque Lab Activity