Everything Science Grade 10

22.4 CHAPTER 22. MECHANICAL ENERGY

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Mechanical energy ESAHN

DEFINITION: Mechanical energy

Mechanical energy is the sum of the gravitational potential energy and the

kinetic energy of a system.

Quantity: Mechanical energy (EM) Unit name: Joule Unit

symbol: J

Mechanical energy,EM, is simply the sum of gravitational potential energy (EP) and the

kinetic energy (EK). Mechanical energy is defined as:

EM=EP+EK

EM=mgh+^12 mv^2

Tip

You may see mechan-
ical energy written as
U. We will not use
this notation in this
book, but you should
be aware that this no-
tation is sometimes
used.

Example 6: Mechanical energy

QUESTION

Calculate the total mechanical energy for a ball of mass 0,15 kg which has a kinetic

energy of 20 J and is 2 m above the ground.

SOLUTION

454 Physics: Mechanics