Level: JHS, Basic 7 | Subject: Integrated Science | Strand: Forces and Energy | Topic: Simple Machines
Read the summary notes first, then try these questions. Go back to the summary notes for this topic.
Part A has 20 tick-box questions. Part B has 5 essay questions with a marking guide at the bottom.
Test Yourself: 20 Objective Questions
Tick one answer for each question, then press Review answer. If your answer is wrong, it will be marked first, then the correct answer will show in green.
1. A machine is a device that
2. The weight to be moved by a machine is called the
3. The force we apply to a machine is the
4. The fixed point on which a lever turns is the
5. A see-saw is an example of a
6. In a first class lever, the fulcrum is
7. A wheelbarrow is an example of a
8. A pair of tweezers is an example of a
9. Scissors work as a
10. A ramp used to load goods onto a truck is an
11. An axe is an example of a
12. A rope over a wheel used to draw water from a well is a
13. A jar lid works on the principle of a
14. Mechanical advantage is calculated as
15. A load of 600 N is lifted with an effort of 200 N. The mechanical advantage is
16. Velocity ratio is the distance moved by the effort divided by the
17. Efficiency of a machine is calculated as
18. A machine has MA = 4 and VR = 5. Its efficiency is
19. No machine is 100% efficient because of
20. Which of these does a machine NOT do?
Essay Questions
- (a) What is a machine? (b) Name four simple machines. (6 marks)
- Describe the three classes of levers and give one example of each. (6 marks)
- A load of 800 N is lifted by an effort of 200 N. Calculate the mechanical advantage. (3 marks)
- A machine has a velocity ratio of 5 and a mechanical advantage of 4. Calculate its efficiency. (4 marks)
- Explain why a machine can never be 100% efficient. Give two ways of improving efficiency. (4 marks)
Essay Questions: Marking Guide for Teachers and Parents
- (a) A device that makes work easier (2). (b) Any four: lever, pulley, inclined plane, wedge, screw, wheel and axle (1 mark each).
- First class: fulcrum between effort and load, e.g. see-saw (2). Second class: load between fulcrum and effort, e.g. wheelbarrow (2). Third class: effort between fulcrum and load, e.g. tweezers (2).
- MA = load ÷ effort (1) = 800 ÷ 200 (1) = 4 (1).
- Efficiency = MA ÷ VR × 100% (1) = 4 ÷ 5 × 100 (1) = 80 (1)% (1).
- Some energy is always wasted as heat because of friction (2). Any two ways: oil or grease moving parts, use smooth surfaces, keep the machine clean (1 mark each, total 2).
Education Always (education.inspiringalways.com). Original practice questions, not official WAEC or BECE questions.