2. WORK
Work has different and rather broad meaning in everyday
language. But in physics concept of work has a very clear
definition.
The product of the component of a force along the
direction of displacement and the magnitude of the
displacement is called work.
3. Consider a constant force F is applied to an object on a
horizontal surface. Under this force if the object is
displaced by an amount x, parallel to the force, then the
work done by the applied force F is defined as the
magnitude of the force times the amount of displacement.
F
W = F.x
x
4. F
θ F cos θ
W =(F cos θ).x
x
Work is a scalar quantity.
1 Joule is the work done by a force of 1Newton
as it acts through a distance of 1metre along the
line of force.
1J = 1N.m
5. PROBLEM
How much work is done on a vacuum cleaner
pulled 3 m by a force of 50 N at an angle of 30˚
above the horizontal?
6. PROBLEM
A weight lifter lifts a set of weights a vertical
distance of 2.00 m. If a constant net force of 350 N
is exerted on the weights, what is the net work done
on the weights?
7. PROBLEM
If 2.0 J of work is done in raising a 180 g apple,
how far is it lifted?
