Analysis Exercise:  The Mechanic and the Wrench

• A person trying to fix her car with a wrench must turn a bolt counterclockwise to loosen it. In what direction is the torque? Is it positive or negative?

Solution





 

• When our intrepid mechanic uses a 6 inch-long wrench, she manages to exert a torque of 35Nm. A neighbor loans her a 24 inch-long wrench. If she exerts the same force on the longer wrench as on the shorter one, what is the maximum torque the original mechanic could provide with the longer wrench?

Solution

• The neighbor, who goes to the gym every day, offers to help when the longer wrench still doesn't loosen the bolt. This neighbor can exert twice the force. What is the maximum torque the neighbor could provide with the longer wrench?

Solution

• Unfortunately, the neighbor's larger muscles do not allow her to reach as far under the car as the car's owner could. Instead of a 90 ^oangle between the applied force and the wrench, the neighbor can only manage a 75^o angle. What is the actual torque applied by the neighbor?

Solution

Now that we understand how to calculate torque, we can establish some problem-solving steps.