This document discusses the meaning, units, and SI unit of measurement for work. Work is defined as the product of the applied force and the distance moved in the direction of the force. The unit for force is the Newton (N), the unit for distance is the meter (m), and therefore the unit for work is the Newton meter (Nm). However, the standard SI unit for work is the Joule (J), where 1 Joule is equal to the work done by a 1 Newton force to move an object 1 meter.

1. Work
Meaning and SI unit of Measurement

2. The contents
• The meaning of work
• The relationship between force and work
• The unit of force
• The unit of distance
• The unit of work
• The SI unit of work

3. The meaning of work
• Work is done if force is applied and the force causes movement.
• The movement should be in the direction of the force.
• If force is applied and no movement results, no work is done.
• Movement cannot occur if there is no force applied
• This means force can be defined as the product of force and
distance.

4. The relationship between force and work
• Force and work are inseparable.
• This has been seen in the meaning of work.
• Work cannot be done without the application of force.
• Force can be applied yet no work is done if the force does not
cause movement.
• Movement cannot occur if force is not applied.
• This means that force is the anchor of work – no force, no work.

5. The unit of force
• Recall that force is a derived quantity.
• It is derived from mass and gravity.
• A gravitational field constant of about 10N is exerted per Kg of
matter on earth.
• Hence to find force we multiply mass and the gravitational field
constant on earth.
• This means the unit of force is the Newton upon cancellation of
the Kg’s (thus Kg × N/Kg = N).

6. The unit of distance
• As you may recall, distance is a fundamental (basic) quantity.
• Thus distance is not expressed in terms of any other quantities.
• The unit for measuring distance is the metre (m) and this unit is
not derived from any other unit.

7. The unit of work
• Recall that we have defined work as the product of force and
distance.
• The word product means multiplication.
• This means to calculate work you multiply force and distance.
• The units of force and distance will give you the unit for work.
• This unit is the Newton metre (Nm).

8. The SI unit for work
• Recall that an SI unit is an internationally recognized unit.
• The Newton metre is not the SI unit of work.
• The SI unit of work is the Joule (J)
• 1J is equal to 1Nm.
• This means 1 Joule is the work done to move 1Kg of a substance
through 1m.

9. END OF PRESENTATION
Thank you for paying attention to this presentation