work energy and power

1. WORK is defined as product of the force and displacement
of an object in the direction of force.

2. Formula of work is W = F x s
F= Force in Newton s =
Displacement in meters. Unit
of work is Joule

3. ENERGY
Energy is the ability to do
work. Unit: joules (J) Many
types, including: •
Mechanical, Elastic,
Gravitational, Kinetic •
Chemical, Thermal, Sound,
Luminous • Nuclear, Radiant,
Magnetic, Electrical •
Potential (stored) e.g.
gravitational potential

4. Energy is the ability to do work.
Potential energy can be
converted to kinetic energy e.g.
gravitational potential As the cart
rolls down the hill, gravitational
potential energy is co

6. Forms of Energy The type of
energy to be covered in this power
point is the Mechanical Energy. In
order to fully cover the subject we
have to start with work, Then study
energy, And later relate them
together.

8. POWER
Power is defined as ability to do
work. SI Unit : Watt (W)
Often also interested in the rate at which the energy
transfer takes place Power is defined as this rate of
energy transfer

9. Work :- Work is said to be done when a
force acts on an object and the object is
displaced in the direction of force. The work
done on an object is the product of the
force applied and the displacement. Work
done = force x displacement W = F X s The
unit of work is joule (J). If F is 1 Newton and
displacement is 1 metre then the work done
is 1Nm or 1 joule (J). So 1 joule is the
amount of work done when a force of I
Newton displaces an object by 1 metre. Eg
:- If a force of 5 N acts on an object is
displaced through 2 m in the direction of
force, then work done is 5 N x 2 m = 10 Nm
or 10 J

10. The work done by a force may be positive or
negative. The work done by a force is positive if the
force and displacement are in the same direction.
The work done by a force if negative if the force and
displacement are in opposite directions. The work
done by a force is zero if there is no displacement.
The work done by a force is zero if the force is
perpendicular to the displacement. Eg :- When we
lift an object the object moves upward in the
direction of force. Here the work done is positive.
But there is the force of gravity acting downward on
the object. The work done by the force of gravity is
negative. Eg :- A porter lifts a luggage of 15 kg from
the ground and puts it on his head 1.5 m above the
ground. Calculate the work done by him on the
luggage. Mass of luggage m = 15 kg, displacement
= 1.5 m, Acceleration due to gravity = 10 ms Work
done W = F x s = mg x s = 15 kg x 10 ms x 1.5 m =
225 kg ms = 225 N m = 225 J -2 -2

11. REFFERENCES
• Amanullah S (2015). Work, energy and power. Available
from slide share
athttps://www.slideshare.net/SheikhAmanullah/workpo
wer-and-energy
• Mishra A(2014). Work ,power and energy. Available
from slide share at
https://www.slideshare.net/shironsheridan/work-
power-and-energy-33070285
• Mizan M(2015). Work energy and power. Available from
slide share at
https://www.slideshare.net/mohd_mizan/chapter-4-
work-energy-and-power
• Months(2009).work ,energy and power. Available from
slide share
athttps://www.slideshare.net/moths/chapter-6-work-
energy-power
• Othukkungal G(2013). WORK, ENERNGY AND POWER.
Available from slide share at
https://www.slideshare.net/tcagokl/work-energy-and-
power-16343881