WORK, ENERGY, POWER

1. POTENTIAL ENERGY ~energy stored in an object due to the position or state of object

1.1. Gravitational potential energy

1.1.1. Work done to lift an object to height : ball bouncing off the floor : child jumping in the air

1.1.2. =work done =mgh m: mass of object (kg) g: acceleration due to gravity (m s-²) h: vertical of height (m)

1.2. Elastic potential energy

1.2.1. Work done to compress or stretch an elastic object with displacement : compress spring : elongated rubber band

1.2.2. = work done = area under the graph =1/2 fx 1/2f = average stretching or compression force X = displacement from the equilibrium position

1.3. SI unit for potential energy=joule

2. KINETIC ENERGY

2.1. Energy possess by object that move • spinning fan • flying bird • rolling ball • vibrating speaker

2.2. SI unit for kinetic energy= joule

3. WORK

3.1. Work = force × displacement W=Fs W= work(Nm) F =magnitude of the (N) S=magnitude of displacement (m)

3.2. Product of the force and displacement in direction of the force

3.3. Work,done when force causing an object to move in the direction of the force SI unit for work=joule 1J=1N×1m

4. POWER

4.1. Rate of doing work

4.2. Power=work done ÷ time taken P=power(w) W=work(J) t= time(s)

4.3. SI unit fo power =watt 1W=1 joule per second (J S-¹)

5. PRINCIPLE OF CONVERSATION OF ENERGY

5.1. New Topic

5.2. Energy cannot be created and cannot be destroyed, but it can transform from one form to another and total amount of energy remains unchanged

5.3. Work is done when energy transform from one to another