Week 1 – Jss 2 Second Term Basic Science Lesson Notes

E-NOTE FOR BASIC SCIENCE JSS2
SCHEME OF WORK FOR SECOND TERM    

 
WEEK 1
WORK, ENERGY AND POWER
Energy is used up when work is done. The energy stored up in our muscular system is made available when we are to do work. The stored up energy (potential energy) is converted to kinetic energy as work is being done.
MEANING OF WORK, ENERGY AND POWER
Work
Work is done whenever a force is applied to cause a body to move. For instance when you lift a bucket from the ground to your head and stand at a point for several hours ; you have only done work by lifting the bucket of water from the ground to your head ,you have done no work in carrying the bucket of water as long as you remain on the spot.
Energy
Energy is the ability to work by exerting a force to move an object through a distance. Anything that is capable of doing work has energy. For instance,a boy running a race of 100 meter has energy because he is able to move some distance. Work and energy are measured in the same unit as the JOULE.
Power
Power is defined as the time rate of doing work. If two boys of the same weight are to climb a flight of stairs of the same height, the boy that gets to the top first is said to have the greater power. This is because he has done the work of moving his weight through that height at a shorter time.

 Hence, in mathematical terms, power is expressed as: power= workdone or energy expended/time taken.
If the workdone is in joules and the time is in seconds, then the power is watts.
1 watt=1 joule per second

 
 Power can also be commonly expressed in kilowatts(KW), megawatt(MW) and horse power(h.p)
1 KW=1,000W
1MW=1,00 0,000W
1 h.p=746W

 EVALUATION
1. Which of the following is not a source of energy? A. Coke b. Coal c. Smoke d .Water
2. ————- is done when a force moves some things through distance.
a. Work b. Energy c. Movement d. Effort
3. The energy obtained is cassava is ———————-
a. Mechanical b. Chemical c. Heat d. Power
4. Abody which exerts force has ——————–
a. Strenght b.pressure c.Energy d.Power
5. The light energy from the sun is called————–
6.The unit of energy is—————————–
SECTION B
1.Define the following
i.Work ii Energy iii.Power
2.Give the unit of measurement of the following.
i.Work ii Energy iii Power.