Join
Topic

Turning Effects of Force

Estimated reading: 2 minutes 481 views Contributors

Turning Effects: Introduction

– The turning effect of a body is called the moment of that force.
– The turning effect produced depends on both the size of the force and the distance from the pivot.
– The moment of a force about a point is the product of the force applied and the perpendicular distance from the pivot (or turning point) to the line of action of the force.
Hence, Moments of a force = Force x perpendicular distance from pivot.

The Law of Moments

– It states that when a body is in balance or in equilibrium, the sum of the clockwise moments equals the sum of anti-clockwise moments.
– The SI units of the moments of a force is Newton metre (Nm).

Practice Example 1

1. A uniform rod of negligible mass balances when a weight of 3 N is at A, weight of 3 N is at B and a weight of W is at C. What is the value of weight W?

Practical Example - Physics Form Two
Solution

Taking moments about the fulcrum, O then
Anti-clockwise moments = (3 x 1) + (3 x 3)
= 3 + 9 = 12 Nm
Anti-clockwise moments = clockwise moments
3 W = 12 Nm
W = 4 N

Practice Example 2

2. The following bar is of negligible weight. Determine the value of ‘x’ if the bar is balanced.

Practical Example - Physics Form Two
Solution

The distance from the turning point to the line of action can be determined as;

Practical Example - Physics Form Two

Clockwise moments = 10 × 30 = 300 N cm,
Anticlockwise moments = 10 × ‘x’ = 10 x. N cm.
Using the principle of moments
Anti-clockwise moments = clockwise moments
10 x = 300, hence x = 30 cm.

Practice Example 3

3. Study the diagram below and determine the value of X and hence the length of the bar.

Practical Example - Physics Form Two
Solution

Clockwise moments = 15x N + 5(X x 20) N
Anticlockwise moments = (20 x 10) + (60 × 10) N cm = 800 N cm.
Anti-clockwise moments = clockwise moments
800 N cm = 15X + 5X + 100
800 n cm = 20X + 100
20X = 700
X = 35 cm.
Therefore, the length of the bar = 40 + 20 + 35 + 20 = 115 cm.

The Lever

-A lever is any device which can turn about a pivot or fulcrum.
-The applied force is called the effort and is used to overcome the resisting force called the load.

Practical Example - Physics Form Two

Practice Example 1

Consider the following diagram. (The bar is of negligible mass). Determine the effort applied.

Practical Example - Physics Form Two
Solution

Taking moments about O. Then, clockwise moments = effort x 200 cm.
Anticlockwise moments = 200 x 30 cm.
Effort = (200 x 30)/ 200 = 30 N.

Turning Effects of Force - PreviousMeasurement IINext - Turning Effects of ForceEquilibrium and Center of Gravity (CoG)

Related articles

Leave a Comment


Share this Doc

Turning Effects of Force

Or copy link

CONTENTS

Made with ❤️ by Darasa Huru

Learning BaseContact

Thrive! English Standard Four PDF-Free Download

Do you want to see your primary school student express themselves with absolute

Excel Now! Hisabati Darasa La Tatu PDF [Download Bure]

Je, unatafuta njia rahisi ya kumsaidia mwanafunzi wako kufanya vizuri na kupenda

Thrive! Civic and Moral Standard Three PDF [Free Download]

Looking for the official TIE Civic and Moral Standard Three textbook? Access thi

Thrive! English Standard Three PDF-Free Download

Looking for the official TIE English Standard Three textbook? Grab this free dig

Learn with Joy: Social Studies Standard Three PDF Free

Need the official TIE Social Studies Standard Three textbook? Get the free digit

Ignite Curiosity! Download the Official Standard 3 Science Technology Book Free

Looking for the official TIE Science and Technology Standard Three textbook? Gra

Master Mathematics Standard Three Textbook PDF [Free Download]

Need the Mathematics Standard Three textbook? This free PDF follows the Tanzania

English Standard Five

Are you looking for the English Standard Five textbook for primary schools in Ta

Standard Seven

Excel! Social Studies Standard Four PDF [Free Download]

Need the Social Studies Standard Four textbook? This free PDF follows the Tanzan

Thrive! Civic and Moral Education Standard Four PDF Free

Download Civic and Moral Education Standard Four book PDF. Covers TIE syllabus t

Standard Six

Chat Icon Close Icon

Subscribe

×
Cancel