Moments Flashcards
What is a moment ?
The turning effect of a force.
What is the equation to calculate the
moment of force ?
Moment of force (Nm) = Force (N) x Distance (m) - the perpendicular distance from the pivot to the line of action of the force.
M = Fd
How does a moment happen ?
A force, or several forces, can cause an object to rotate.
The force on a spanner causes a turning effect or moment on the but ( which acts as a pivot). A larger force or a longer distance spanner would mean a larger moment, how would you get to the maximum moment ?
You need to push at right angles to the spanner. Pushing at any other angle means a smaller distance, so smaller moment.
What do levels do ?
They increase the distance from the pivot at which the force is applied. Since M = Fd this means less force is needed to get the same moment. This means levers make it’s easier to do work, e.g. lift a load or turn a nut.
What are gears used for ?
To transmit the rotational effect of a force from one place to another.
What are different sized gears used to do ?
To change the moment of the force. A force transmitted to a larger gear will cause a bigger moment, as the am distance to the pivot is greater. The larger gear will turn slower than the smaller gear.
