Moments
Jonny Nelson introduces an animated explanation of moments, levers and gears
A force or system of forces may cause an object to turn. A A turning effect of a force. is the turning effect of a force. Moments act about a point in a clockwise or anticlockwise direction. The point chosen could be any point on the object, but the A point around which something can rotate or turn. - also known as the fulcrum - is usually chosen.
The magnitude of a moment can be calculated using the equation:
moment of a force = force 脳 distance
\(M = F~d\)
This is when:
- moment (M) is measured in newton-metres (Nm)
- force (F) is measured in newtons (N)
- distance (d) is measured in metres (m)
Example
A force of 15 N is applied to a door handle, 12 cm from the pivot. Calculate the moment of the force.
First convert centimetres into metres:
12 cm = 12 梅 100 = 0.12 m
Then calculate using the values given in the question:
\(M = F~d\)
\(M = 15 \times 0.12\)
\(M = 1.8~Nm\)
Question
A force of 40 N is applied to a spanner to turn a nut. The perpendicular distance is 30 cm. Calculate the moment of the force.
\(M = F~d\)
\(30~cm = 0.30~m\)
\(M = 40 \times 0.30\)
\(M = 12~Nm\)