The directed segment joining the origin to the point A (2. 2) completely
represents a force. Find the point on the X-axis about which the moment of the
force is 10 units.
Answers
Answer:
When we consider cases where forces act on a body of non-zero size (i.e. not a particle),
the main new aspect that we need to take account of is that such a body can rotate, as
well as move through space, under the action of forces.
(The complete treatment of cases like this requires more theory of vectors than we have
covered, so we shall consider only two dimensional (2-D) cases. The bodies themselves do
not have to be 2-D; the important point is that all the forces (more precisely, the lines of
action of the forces) should lie in or be parallel to a single plane. Such forces are said to
be coplanar.)
If forces act on a finite size body they may produce a turning effect. This is measured by
the moment of the force.
Wheel with fixed centre.
The further away F is from the centre, the
greater the turning effect.
b
F
rotation
The moment of a force F (applied at a point P) about a point A is equal to ±F d where:
• F is the magnitude of the force.
• d is the perpendicular distance from A to the line of action of the force.