Grade 10 power mechanics – Overview of Power Mechanics as a Learning Area Quiz
1. What is the primary focus of the subject Power Mechanics as taught in Kenyan technical schools?
Power Mechanics focuses on how mechanical power is produced, transmitted and applied in machines and systems, which is the basis for training technicians and artisans.
2. Which of the following is a common source of mechanical power in rural Kenyan farms?
Rural farms commonly use human and animal power and small internal combustion engines (diesel or petrol) for tasks like ploughing and pumping water.
3. What is the difference between power and energy in simple terms?
Power measures how quickly work is done (e.g., kilowatts), while energy measures the total amount of work or fuel used (e.g., kilowatt-hours).
4. Which unit is commonly used in Kenyan schools to measure mechanical power?
Kilowatt (kW) is a standard unit for measuring power and is commonly taught and used for engines and motors.
5. A common method of transmitting mechanical power between shafts is:
Mechanical power is transmitted between shafts using gears, belts, chains and couplings — basic power transmission components in machines.
6. Which safety item is essential when working with engines and power tools in the workshop?
Using PPE (gloves, goggles, boots, overalls) reduces risk of injury from hot parts, flying debris and chemical spills in a workshop.
7. What is a prime mover in power mechanics?
Prime movers convert energy (fuel, electricity) into mechanical power; common examples include internal combustion engines and electric motors.
8. Why is routine maintenance important for power machines used on Kenyan farms and construction sites?
Routine maintenance like oil changes, filter cleaning and adjustments prevents failures, saves costs and keeps equipment reliable.
9. Which of the following best describes a two-stroke petrol engine used in small machines?
Two-stroke engines complete intake/compression and power/exhaust in two piston movements and commonly require oil mixed with petrol for lubrication.
10. What role do gears play in power transmission systems?
Gears alter rotational speed and torque, allowing adaptation of prime mover output to the needs of the driven machine.
11. Which instrument would you use to measure the rotational speed of a motor shaft?
A tachometer measures rotational speed (revolutions per minute, RPM) of shafts and motors, important for setting and diagnosing machines.
12. What is the environmental concern most associated with poorly maintained diesel engines?
Poor maintenance leads to incomplete combustion, producing smoke and harmful emissions that increase air pollution and health risks.
13. Which career is most directly related to Power Mechanics at the technical level?
Power Mechanics trains students for technical roles such as diesel technicians, mechanics for agricultural and construction machinery.
14. Why is understanding simple mechanical drawings important in Power Mechanics?
Mechanical drawings provide visual information about parts and assemblies, essential for correct maintenance and fabrication.
15. Which of these is a power transmission accessory commonly used on small tractors and pumps?
A PTO shaft transfers mechanical power from a tractor engine to implements like pumps and tillers; it is common in agricultural equipment.
16. What is the correct basic safety practice before starting any repair on a machine?
Isolating power and securing moving parts prevents accidental starts and reduces risk of injury during maintenance.
17. Which is an example of a hydraulic power application in Kenyan settings?
Hydraulic systems use fluid pressure to move heavy loads and are used in loaders, jacks and some farm implements.
18. What is meant by 'power transmission efficiency'?
Efficiency refers to how much of the energy supplied by the prime mover reaches the driven component after losses from friction, heat and slippage.
19. Which fuel is generally more energy-dense and commonly used in heavy Kenyan equipment?
Diesel has high energy density and is commonly used in heavy equipment and generators due to its efficiency and torque characteristics.
20. When teaching Power Mechanics, which practical activity helps students learn about power transmission?
Hands-on activities like assembling belt-and-pulley systems help students understand speed and torque changes and practical installation issues.
21. Which of the following best describes preventive maintenance in Power Mechanics?
Preventive maintenance involves scheduled inspections and service tasks to detect wear early and prevent costly breakdowns.
22. How does a gearbox affect the performance of a machine?
A gearbox changes the ratio between input and output speed and torque, allowing machines to perform different tasks efficiently.
23. Which is a simple classroom experiment to demonstrate the concept of torque?
A lever experiment shows how force applied at different distances from a pivot changes the turning effect (torque), demonstrating the principle clearly.
24. Why do technicians record machine operating hours and service dates?
Recording hours and service dates helps plan maintenance tasks at the right intervals, extending life and preventing unexpected failures.
25. Which of these is a direct benefit of studying Power Mechanics for a Kenyan student aged 15?
Studying Power Mechanics provides practical technical skills that are directly useful for careers and everyday mechanical tasks in agriculture and industry.