# Torque HSC Questions that will scare you

Torque HSC questions are renowned for being scary. One of my students who had never lost a mark in a HSC physics internal exam thought torque questions were going to be his downfall. Whilst the concept of torque is rather simple, realistically just a mathematical formula to explain what to do to open a door, some of the related questions can be challenging. My student and I sat down and we worked out the variations in the torque questions and what principles apply. As a result of this analysis they joked that all torque questions are actually the same and smiled when they saw it in their HSC physics paper. It must of worked because they ended up getting a band 6.

Torque is that feeling when you try to open a door. Ever noticed how it is really easy to open a door when the door handle is far away from the hinge, but when it is close, you have to try really hard to move the door.

Torque can also be referred to as the momentmoment of force or rotational force.

This concept originated in Archimedes’ study of the use of levers and is reflected in his famous quote: “If you give me a place to lean on, I can move the earth.” Torque can be thought of as the rotation of an object about a particular axis, much like a linear force pushes or pulls. Torque is defined as the product of the magnitude of the force and the perpendicular distance from the axis of rotation to the line of action of the force. The law of conservation of energy can also be used to understand torque. The symbol for torque is usually the lowercase Greek letter tau. When called a moment of force, it is commonly denoted as M.

We can describe torque mathematically:

r is the distance of the object from the pivot point (m)

F is the force that is applied (N)

Theta is the angle the force is applied at (degrees)

𝜏 or tau is the torque (N.m)

### Learning Summary

• Torque is measured in Nm and determines the amount of force required to make something rotate.

## Exam-style Torque HSC Questions.

Question 1.

From the 2019 HSC Physics Question 26

Question 2.

From the 2020 HSC physics Question 23 – this is a cross module question.

Question 3.

From the 2021 HSC Physics Question 21 – this is a cross module question.