Grade 10 power mechanics β Evolution of Motor Vehicles Quiz
1. Who is widely credited with building the first practical gasoline-powered motorcar?
Karl Benz built and patented one of the first practical gasoline-powered cars in 1886, often regarded as the first true automobile.
2. In which decade was the first practical petrol-powered car patented by Karl Benz?
Karl Benz patented his motorcar in 1886, which falls in the 1880s decade.
3. Which type of engine uses compression ignition rather than a spark to ignite fuel?
Diesel engines use compression to heat air and ignite the diesel fuel without a spark, unlike petrol engines which use spark ignition.
4. Which sequence correctly lists the four strokes of a four-stroke (Otto cycle) petrol engine?
The four-stroke Otto cycle runs intake, compression, power (combustion), then exhaust in that order.
5. Who invented the diesel engine, which offered higher efficiency for some vehicles and machines?
Rudolf Diesel developed the diesel engine in the 1890s, designed for higher thermal efficiency using compression ignition.
6. What was the main effect of Henry Ford introducing the moving assembly line for cars?
Ford's moving assembly line greatly increased production speed and lowered manufacturing costs, making cars affordable for many families.
7. Why did early electric cars (late 1800sβearly 1900s) lose popularity compared to petrol cars?
Early electric vehicles had short ranges and battery limitations, while petrol became cheaper and internal combustion engines improved, reducing EV popularity then.
8. What is the primary fuel used by most heavy buses and many public service vehicles in Kenya today?
Diesel is commonly used in heavy buses and many public service vehicles because diesel engines provide good torque and fuel economy for heavy loads.
9. What is the main purpose of a vehicle's transmission (gearbox)?
The transmission adjusts gear ratios between the engine and the wheels so the engine runs at suitable speed and torque under varying conditions.
10. Which part of a motor vehicle stores electrical energy to start the engine and power circuits when the engine is off?
The battery stores electrical energy used to start the engine and to supply electrical systems when the engine isn't running.
11. What replaced horse-drawn carts as the main means of city transport during the early 20th century?
Motor vehicles such as cars and buses became widespread in cities, replacing horse-drawn transport for speed, capacity and reliability.
12. What is a key environmental benefit of hybrid vehicles compared with conventional petrol cars?
Hybrids combine an internal combustion engine with an electric motor to reduce fuel consumption and tailpipe emissions compared with conventional petrol vehicles.
13. In Kenya, what is a 'matatu' commonly used to describe?
A matatu is a commonly used shared minibus or van that provides public transport services in Kenyan towns and cities.
14. Which safety system helps prevent wheels from locking during heavy braking and improves steering control?
ABS automatically pulses brakes to prevent wheel lock-up, helping the driver maintain steering control during hard braking.
15. What is the main role of a catalytic converter in a vehicle's exhaust system?
A catalytic converter uses chemical reactions to convert pollutants like carbon monoxide and nitrogen oxides into less harmful gases before they exit the exhaust.
16. Which greenhouse gas is produced in large amounts by burning petrol and diesel in vehicle engines?
Burning fossil fuels in engines releases carbon dioxide, a major greenhouse gas contributing to climate change.
17. Which infrastructure is most essential for everyday use of motor vehicles in towns and rural areas?
Road networks are the primary infrastructure that allows motor vehicles to move people and goods within towns and between regions.
18. Why are four-stroke engines usually preferred over two-stroke engines for modern cars?
Four-stroke engines burn fuel more completely and emit fewer pollutants than typical two-stroke designs, making them better for cars.
19. What is the primary function of a vehicle gearbox when climbing a steep hill?
Selecting a lower gear increases torque at the wheels, helping the vehicle climb steep hills without stalling the engine.
20. What is the purpose of a vehicle's exhaust muffler?
A muffler contains chambers and baffles that reduce the sound of exhaust gases as they leave the vehicle.
21. What does the term 'horsepower' measure in a vehicle?
Horsepower is a unit used to express the rate at which an engine can do work β its power output.
22. In an internal combustion engine, what energy conversion mainly takes place?
Internal combustion engines burn fuel to convert chemical energy into heat and pressure, which is then converted into mechanical motion.
23. Which technological development has most directly helped reduce harmful exhaust emissions from modern petrol cars?
Catalytic converters chemically reduce pollutants in exhaust gases, significantly lowering harmful emissions from petrol vehicles.
24. What is a key advantage of battery electric vehicles (EVs) compared with petrol cars when we consider tailpipe emissions?
EVs have zero tailpipe emissions because they do not burn fuel; however, total emissions depend on how the electricity is produced.
25. How did the spread of motor vehicles help Kenya's economy in the 20th century?
Motor vehicles improved mobility and logistics, which supported markets, created transport and repair jobs, and helped trade across regions.