AEN 201A: Farm Power and Machinery (Quiz 1)
The answer options given, are all limitations with the use of human labour but the most important is the power output required for work, which is low in humans.
The correct answer is C
The answer options given, are all limitations with the use of human labour but the most important is the power output required for work, which is low in humans.
The correct answer is C
CORRECT ANSWER & EXPLANATION
Statements I, II and III are all true about internal combustion engines.
First the chemical energy of the fuel is converted to Heat and then finally to mechanical power output.
Because the combustion of the fuel takes place in a closed chamber, it is called internal combustion engine.
The correct answer is D.
CORRECT ANSWER & EXPLANATION
Statements I, II and III are all true about internal combustion engines.
First the chemical energy of the fuel is converted to Heat and then finally to mechanical power output.
Because the combustion of the fuel takes place in a closed chamber, it is called internal combustion engine.
The correct answer is D.
I. Fuel usage
II. Fuel ignition
III. Fuel consumption
Internal combustion engines are classified by the following attributes...
a) the types of fuel used (petrol, diesel, LPG, hydrogen, biodiesel etc),
b) method of fuel ignition (i.e spark ignition or compression ignition),
c) by the cycle of operation (i.e. 4-stroke, 2-stroke),
d) the methods of cooling,
e) degree of mobility,
f) engine speed,
g) output power,
h) number of cylinders in the engine block.
The best option is therefore A.
Internal combustion engines are classified by the following attributes...
a) the types of fuel used (petrol, diesel, LPG, hydrogen, biodiesel etc),
b) method of fuel ignition (i.e spark ignition or compression ignition),
c) by the cycle of operation (i.e. 4-stroke, 2-stroke),
d) the methods of cooling,
e) degree of mobility,
f) engine speed,
g) output power,
h) number of cylinders in the engine block.
The best option is therefore A.
In air-cooled engines, a fan is normally provided to aid circulation of fresh atmospheric air round the engine.
In water-cooled engines, a fan is installed to blow air through the radiator, to assist in heat dissipation.
The correct answer is therefore B
In air-cooled engines, a fan is normally provided to aid circulation of fresh atmospheric air round the engine.
In water-cooled engines, a fan is installed to blow air through the radiator, to assist in heat dissipation.
The correct answer is therefore B
CORRECT ANSWER & EXPLANATION
In water-cooled engines, the flow of water is usually assisted with the use of a water pump to circulate water around the engine.
A Thermostat in a water-cooled engine restricts water flow until the engine reaches a normal working temperature. When the water temperature rises, the thermostat allows the valves to open to enable water to flow through the radiator and by so doing, provide the cooling effect.
When the water is excessively hot, the thermostat switches on the fan and when it has been cooled to normal temperature, the fan is switched off. If the thermostat is faulty the engine temperature will rise tremendously.
A dirty or inadequate coolant in the radiator can also be the cause.
Therefore, the right answer is D
CORRECT ANSWER & EXPLANATION
In water-cooled engines, the flow of water is usually assisted with the use of a water pump to circulate water around the engine.
A Thermostat in a water-cooled engine restricts water flow until the engine reaches a normal working temperature. When the water temperature rises, the thermostat allows the valves to open to enable water to flow through the radiator and by so doing, provide the cooling effect.
When the water is excessively hot, the thermostat switches on the fan and when it has been cooled to normal temperature, the fan is switched off. If the thermostat is faulty the engine temperature will rise tremendously.
A dirty or inadequate coolant in the radiator can also be the cause.
Therefore, the right answer is D
The four-stroke engine gives greater engine economy, is quieter running, develops more overall power, runs better at lower revolutions per minute and has a wider speed range than the two-stroke engine.
The two-stroke engine develops smoother torque due to the fact that it has one power stroke per each revolution, whereas the four-stroke engine has one power stroke for two crankshaft revolutions.
The correct answer is therefore B
The four-stroke engine gives greater engine economy, is quieter running, develops more overall power, runs better at lower revolutions per minute and has a wider speed range than the two-stroke engine.
The two-stroke engine develops smoother torque due to the fact that it has one power stroke per each revolution, whereas the four-stroke engine has one power stroke for two crankshaft revolutions.
The correct answer is therefore B
Before draft animals can be used for farm work, they have to be trained. During training animals learn to respond to human languages and how to pull the various implements.
The best age to start training the animal is between 2½ and 3 years.
Approach the animal and call its name. Don’t force the animal if its cannot put up to a constant performance every day and avoid beating and being hostile.
Learn the speed, the temperament and the character of your animal and adjust to them.
Move from an easy step to a more difficult step. In other words, start from the known to the unknown.
The right answer option is therefore E
Before draft animals can be used for farm work, they have to be trained. During training animals learn to respond to human languages and how to pull the various implements.
The best age to start training the animal is between 2½ and 3 years.
Approach the animal and call its name. Don’t force the animal if its cannot put up to a constant performance every day and avoid beating and being hostile.
Learn the speed, the temperament and the character of your animal and adjust to them.
Move from an easy step to a more difficult step. In other words, start from the known to the unknown.
The right answer option is therefore E
A three cylinder four stroke engine employs the 120o crank angle.
The correct answer is A.
A three cylinder four stroke engine employs the 120o crank angle.
The correct answer is A.
CORRECT ANSWER & EXPLANATION
In a two-stroke engine, two piston strokes complete one cycle.
There is no definite intake and exhaust, but ports which get covered and uncovered as the piston moves up and down.
Hence, there is power immediately after compression of the fuel mix.
At 540 o of crank travel, there will be compression in cylinder 2.
The right answer is E
CORRECT ANSWER & EXPLANATION
In a two-stroke engine, two piston strokes complete one cycle.
There is no definite intake and exhaust, but ports which get covered and uncovered as the piston moves up and down.
Hence, there is power immediately after compression of the fuel mix.
At 540 o of crank travel, there will be compression in cylinder 2.
The right answer is E
CORRECT ANSWER & EXPLANATION
A Diesel engine has about 40% lower fuel economy than a petrol engine.
It is therefore more economical to run but the fuel is not volatile at ordinary temperatures, and as a results needs higher compression ratios for ignition.
There is also more oil contamination with diesel engines.
The correct answer is D.
CORRECT ANSWER & EXPLANATION
A Diesel engine has about 40% lower fuel economy than a petrol engine.
It is therefore more economical to run but the fuel is not volatile at ordinary temperatures, and as a results needs higher compression ratios for ignition.
There is also more oil contamination with diesel engines.
The correct answer is D.
CORRECT ANSWER & EXPLANATION
Engine temperature is mainly controlled by the
a) radiator size,
b) thermostat,
c) water level or head of water in the radiator,
d) the water pump, and
e) fans.
Answer Options I and III are true. Therefore the correct answer is D
CORRECT ANSWER & EXPLANATION
Engine temperature is mainly controlled by the
a) radiator size,
b) thermostat,
c) water level or head of water in the radiator,
d) the water pump, and
e) fans.
Answer Options I and III are true. Therefore the correct answer is D
The correct answer is C, because the others are single grade oils.
C is multi-grade oil, which contains additives to prevent excessive thickening and thinning when temperature reduces or increases.
The correct answer is C, because the others are single grade oils.
C is multi-grade oil, which contains additives to prevent excessive thickening and thinning when temperature reduces or increases.
The correct answer is A
The correct answer is A
CORRECT ANSWER & EXPLANATION
SAE 10, SAE 20, SAE 30 and SAE 40 generally denote engine oils.
Higher numbers like SAE 50, 70, 90, 140 denote gear and transmission oils.
So from the answer options, the possible correct option could be either A or B.
Since Africa is generally hot, a higher oil viscosity ("thickness") will be desired.
The correct answer is A
CORRECT ANSWER & EXPLANATION
SAE 10, SAE 20, SAE 30 and SAE 40 generally denote engine oils.
Higher numbers like SAE 50, 70, 90, 140 denote gear and transmission oils.
So from the answer options, the possible correct option could be either A or B.
Since Africa is generally hot, a higher oil viscosity ("thickness") will be desired.
The correct answer is A
CORRECT ANSWER & EXPLANATION
The bullock and Zebu are all suitable draft animals.
The Gudali breed is heavy and strong breed of the Zebu. A very good draft animal, but more susceptible to diseases and also not as common as other Zebu breed (the Red M’bororo and the white M”bororo or Aku).
The Gudali is also more expensive to purchase making is unsuitable for draft animal technology in Africa.
The best option is therefore D
CORRECT ANSWER & EXPLANATION
The bullock and Zebu are all suitable draft animals.
The Gudali breed is heavy and strong breed of the Zebu. A very good draft animal, but more susceptible to diseases and also not as common as other Zebu breed (the Red M’bororo and the white M”bororo or Aku).
The Gudali is also more expensive to purchase making is unsuitable for draft animal technology in Africa.
The best option is therefore D
The camshaft controls the opening and closure of the valves in the engine cylinders.
Each cylinder is fitted with a shaft with two cams (one to operate the inlet valve and the other to operate the exhaust valve) machined along the length of the camshaft.
The correct answer is A
The camshaft controls the opening and closure of the valves in the engine cylinders.
Each cylinder is fitted with a shaft with two cams (one to operate the inlet valve and the other to operate the exhaust valve) machined along the length of the camshaft.
The correct answer is A
CORRECT ANSWER & EXPLANATION
This question relates to the classification of engines based on engines power output.
It can be noticed that options A to D operate on single-cylinder, air cooled, with a maximum speed between 3000 and 4000 rpm.
The maximum power output for mowers, motor cycles, concrete mixers, and power tillers is between 1-10kW.
Hence, the odd one out is the farm tractor, which mostly have power outputs between 20-100 kW
The correct answer is E
CORRECT ANSWER & EXPLANATION
This question relates to the classification of engines based on engines power output.
It can be noticed that options A to D operate on single-cylinder, air cooled, with a maximum speed between 3000 and 4000 rpm.
The maximum power output for mowers, motor cycles, concrete mixers, and power tillers is between 1-10kW.
Hence, the odd one out is the farm tractor, which mostly have power outputs between 20-100 kW
The correct answer is E