The document discusses mechanical energy, including potential energy which is energy due to position, kinetic energy which is energy due to motion, and mechanical energy which is the sum of potential and kinetic energy. It defines the equations for gravitational potential energy, kinetic energy, and mechanical energy. The document also explains the law of conservation of energy, stating that energy cannot be created or destroyed, and the law of conservation of mechanical energy which states that the total mechanical energy of an isolated system remains constant.

1. 1
Everything Science www.everythingscience.co.za
22. Mechanical energy
Physics: Mechanics
Grade 10

2. 2
Everything Science www.everythingscience.co.za
Potential energy
Potential energy is the energy an object has due to its position or state.
The gravitational potential energy of an object is the energy the object has because of its
position in the gravitational field relative to some reference point.
EP=mgh

3. 3
Everything Science www.everythingscience.co.za
Kinetic energy
The kinetic energy of an object is the energy the object has due to its motion.
EK =
1
2
mv2

4. 4
Everything Science www.everythingscience.co.za
Mechanical energy
The mechanical energy of an object is the sum of the potential energy and kinetic energy of
the object.
EM=EK +EP
EM=mgh+
1
2
mv2

5. 5
Everything Science www.everythingscience.co.za
Conservation of energy
The Law of Conservation of Energy states that energy cannot be created or destroyed, but can
only be changed from one form into another.
The Law of Conservation of Mechanical Energy states that the total mechanical energy of an
isolated system (i.e. no friction or air resistance) remains constant.

6. 6
Everything Science www.everythingscience.co.za
For more practice or to ask an expert for help on this
section see:
www.everythingscience.co.za
Shortcode: ESAHJ

7. 6
Everything Science www.everythingscience.co.za
For more practice or to ask an expert for help on this
section see:
www.everythingscience.co.za
Shortcode: ESAHJ