Homeschool Science for Kids

Science designed for your homeschool family

  • Home
  • Ask Janice
  • Topics
    • Astronomy
    • Biology
    • Chemistry
    • Physics
    • Science Projects
  • FAQ
    • Astronomy
    • Biology
    • Chemistry
    • Earth Science
    • Ecology
    • Engineering
    • Health
    • Physical Science
You are here: Home / Physics / forces and motion / What is Torque?

What is Torque?

May 14, 2016 By Janice VanCleave

Drawing of jar with red lid. Pivot, force, moment arm distance labeled.

Torque

  • Objects that rotate experience torque.
  • Objects that rotate turn around some fixed point.
  • When measuring torque, the point of rotation is called the pivot point.
  • Torque is the product of force times force’s distance is from the pivot point.

Everyday Examples of Torque

1. Opening the lid on a jar is caused by torque, and the center of the lid is the pivot point. The distance is measured from the pivot to the edge of the lid where the force is applied.

2. Picture of a merry-go-round in a park. A merry-go-round rotates about a center point. Thus, force applied to the merry-go-round causes it to turn about its axis, center point.

In summary, torque is a turning force. Torque can be measured using this equation:
Torque= force x distance

Teaching Tips from Janice

During my teaching career, I taught math and science for one year on an army base in Germany. My classroom was in a metal quonset hut behind the main school building. Wind blew through the crack around the windows causing the curtains to flutter. I just wore more clothes to stay warm. But the great thing about this building was it had lots of room and I was the only teacher using it. YEA!

There was a lot of construction work being done around the school by local Germans. I spoke no German and few of the workers spoke English, but I managed to get a a saw-horse and board transported to my classroom. With the board placed across the saw-horse the materials were transformed into a  a see-saw.  My students were so excited.

I used the see-saw to teach basic algebra. I asked two boys to sit on the board and move back and forth from the center until they could balance on the board. This meant that they could hold their legs up and the board would remain relatively horizontal for a few seconds. The distance each boy was sitting from the pivot point of the see-saw was measured. Next, a bathroom scale was used to measure the force weight of ONLY one of the boys.

Challenge:

Use this formula F1 x d1 = F2 x d2 to calculate the weight of the second boy.

It doesn’t matter what units are used to measure the force weight or distance. A bathroom scale was used and weight was measured in pounds, thus the unknown weight was in pounds. The distance unit was centimeters. Challenge Math Problem.

Facts:
F1= weight of Juan= ?
d1= distance of Juan from the pivot= 100 cm

F2= weight of Tyler= 90 lbs
d2= distance of Tyler from the pivot= 120 cm

F1 x d1 = F2 x d2
F1 =F2 x d2/d1

Answer: Juan weighs 108 lbs. 

Check the accuracy of your calculations. Have Juan use the bathroom scales to measure his weight. Were the calculations correct??? If not, give reasons for the error.

The diagram shows a balanced see-saw.
This is because the torque on each end of the board is equal. Diagram of see-saw representing torque and algebra equation.

Teaching the Fun of Math provides teaching tips for introducing algebra problems. Student worksheets are provided. 
Janice VanCleave's Resource for Teaching Math to Kids

 

Share this:

  • Tweet
  • Click to email a link to a friend (Opens in new window) Email
  • Click to print (Opens in new window) Print

Related

No related posts.

Filed Under: forces and motion, Physics, torque Tagged With: algebra, merry-go-round, pivot point, see-saw algebra, torque, turning forces

Copyright © 2025 Homeschool Science For Every Kid · Log in