CHAPTER 8. WORK, ENERGY AND POWER 8.3
Capacity to do Work ESCEF
Energy is the capacity todo work. When positivework is done on an object, the system
doing the work loses energy. In fact, the energy lost by a system is exactly equal to the
work done by the system. An object with larger potential energy has a greater capacity
to do work.
Example 4: Work Done on a System
QUESTIONShow that a hammer of mass 2 kg does more workwhen dropped from a height
of 10 m than when dropped from a height of 5m. Confirm that the hammer
has a greater potential energy at 10 m than at 5m.SOLUTIONStep 1 : Determine what is given and what is required
We are given:- the mass of the hammer, m =2 kg
- height 1, h 1 =10 m
- height 2, h 2 =5 m
We are required to show that the hammer does more work
when dropped from h 1 than from h 2. We are also required
to confirm that the hammer has a greater potential energy at
10 m than at 5 m.
Step 2 : Determine how to approach the problem