Get premium membership and access revision papers, questions with answers as well as video lessons.

Physics K.C.S.E Revision. Question Paper

Physics K.C.S.E Revision.

Course:Secondary Level

Exam Year:2011

Shiners Girls High School.

Physics K.C.S.E Revision.

Topic: Work, Power, Energy and Machines.

Take g=10N/kg
1hp=745W.
1. A stationary mass of 20kg exploded into two parts: one part of mass 4 kg moved off with a K.E of 80kJ. What was the K.E of the other part?

2. A 30 g bullet moving at 400 m/s struck and stuck to a block of wood of mass 10 kg resting on a rough horizontal floor where coefficient of friction is 0.6. How far did the block slide before coming to rest?

3. A boy pushes a crate of vehicle spare parts on a floor where resistance due to friction is 250 N. If he manages a 0.4 m/s steady speed,
a. What is his power?
b. This boy eats ugali whose energy content is 5.04 MJ/kg. His body is only 36% efficient. If he works 8 hours per day, recommend the minimum intake of ugali he requires.
c. What you are recommending is even too little. Give the most important reasons why.

4. An 80% efficient electric pump is found to raise water from a depth of 16m and pump it into a tank 4m above ground at a rate of 120 litres per minute. Determine the minimum electric power necessary to run the pump.

5. At a hydropower generating station, 20 litres of water fall every second onto turbines situated 40m below the dam.

a. What is the maximum power available?
b. If only 4.4 MW is available, what is the efficiency of this set-up?

6. A footballer kicks a ball towards a wall. The ball bounces back with a slight reduced speed. Trace all the energy changes from just before the ball is kicked to the time it has bounced off the wall.

7. How much electric energy must be supplied to an electric motor to raise an elevator having a mass of 4 megagrams a distance of 40m? Assume that 10% of the electric energy supplied to the motor is lost in the form of heat.

8. A lamp draws a 2-A current when connected to a 120-V source. What is the power rating of the lamp?

9. What is the efficiency of an electric hoist if 60,000 J of electric energy has to be supplied to the motor in order to raise a 300-kg mass through 18 m?

10. What electric power input must e provided to an electric motor which develops mechanical energy at the rate of 24 hp with an efficiency of 85%?

Physics K.C.S.E Revision. Question Paper

More Question Papers

Popular Exams

Mid Term Exams

End Term 1 Exams

End Term 3 Exams

Opener Exams

Full Set Exams