1. The width of belt is 15 cm and maximum tension per cm width is not to exceed 12 kg. T1/T2=2.25. Diameter of driver=1m and it makes 220 rpm. Find the horse power that can be transmitted.
a) 11.35 HP
b) 10.23 HP
c) 12.12 HP
d) 9.86 HP
Discussion
Explanation: Maximum tension = 12 * 15 = 180kg
We know that
T = T1 + TC = 180
And, Tc = T/3
Tc = 180/3 = 60 kg
T1 = T-Tc = 180 – 60 = 120kg
T2 = T1/2.5 = 120/2.25 = 53.33 kg
P = (T1-T2) v = (T1 – T2) * 2π Nr
P = (120 – 53.33) * 2\pi * \(\frac{220}{75*60}*\frac{1}{2} \)
P = 10.23 HP.
2. A tractor has belt speed of 1000 m/min at normal engine speed. A feed mill has a recommended speed of 2100 rev/min. Find the size of pulley, needed on the Feed mill.
a) 14.28 cm
b) 12.14 cm
c) 19.11 cm
d) 15.16 cm
Discussion
Explanation: Belt speed (V) = 1000 m/min
V = πDn
πDn = 1000
D = \(\frac{1000}{πn}=\frac{1000}{π*2100}\)=0.1516 m
Required size of pulley = 15.16 cm.
3. A tractor has the following specifications:
i) Engine speed = 2000 rev/min
ii) Rear wheel diameter = 115 cm
iii) Travel speed = 3 km per hour
What will be the ratio between crankshaft speed and rear axle speed?
a) 220.98: 1
b) 129.75: 1
c) 144.50: 1
d) 98.75: 1
Discussion
Explanation: Travel speed 3 km/h = 50 m/min
Rear wheel diameter = 115 cm = 1.15 m
Linear speed of tractor = πDn
πDn = 50
n = \(\frac{50}{πD}=\frac{50}{π*1.15}\) = 13.84
Required speed ratio = \(\frac{Crankshaft \, speed}{Rear \, wheel \, speed}=\frac{2000}{13.84}\) = 144.50:1
4. If it desired to obtain 160 kgm torque at the transmission output shaft, what gear ratio would be necessary if transmission efficiency is 96% and the input torque is 15 kg m?
a) 1:10
b) 1:11
c) 1:12
d) 1:13
Discussion
Explanation: Torque at transmission input shaft = 15 * \(\frac{96}{100}\) = 14.4 kg-m
Required gear ratio = \(\frac{14.4}{160}\) = 1:11
5. Find the gear ratio of a tractor of its final drive of tractor has 1.2 m tractor wheel and forward speed of 5km/h. When engine is running at 1000 rpm if reduction in transmission is 3:1
a) 4.3:1
b) 3.3:1
c) 2.3:1
d) 5.3:1
Discussion
Explanation: Actual speed of tractor (va) = \(\frac{5*5*60}{18}\) = 83.33 m/min
va = rω = r.2πN
N = \(\frac{v}{2πr}=\frac{83.33}{2π*0.6}\) = 22.11
G.r = \(\frac{1000}{3*3.5*22.11}\) = 4.3:1.
6. Which classification of tillage involves initial major soil working operation?
a) Secondary tillage
b) Primary tillage
c) Tertiary tillage
d) Primary & Secondary tillage
Discussion
Explanation: Primary tillage is normally designed to reduce soil strength, cover plant materials, and rearrange aggregates. The operations performed to open up any cultivable land with a view to prepare a seed bed for growing crops is known as Primary tillage.
7. Which primary tillage operation is performed to cut, break and invert the soil partially or completely?
a) Ploughing
b) Winnowing
c) Threshing
d) Harrowing
Discussion
Explanation: The main implement for primary tillage is plough used for ploughing operations. Ploughing is the primary tillage operation, which is performed to cut, brake and invert the soil partially or completely. Ploughing essentially means operating the upper crust of the soil, breaking the clos and making the soil suitable for sowing seeds.
8. What type of mouldboard is short but broader with a relatively abrupt curvature?
a) Sod or breaker
b) Slat
c) Stubble
d) General purpose
Discussion
Explanation: Stubble type’s relatively abrupt curvature lifts, breaks and turns the furrow slice. Its curvature is not gradual but it is abrupt along the top edge. This causes the furrow slice to be thrown off quickly, pulverising it much better than the other types of mouldboard.
9. A flat plate which bears against and transmits lateral thrust of the plough bottom to the furrow wall is known as __________
a) Landside
b) Tail piece
c) Jointer
d) Coulter
Discussion
Explanation: Landside helps to resist the side pressure exerted by the furrow slice on the mouldboard. It also helps in stabilizing the plough while it is in operation. Landside is fastened to the frog with the help of plough bolts. The rear bottom end of the landside is known as heel which rubs against the furrow sole.
10. Which plough accessory is used to turn over a small ribbon like furrow slice directly in front of the main plough bottom?
a) Coulter
b) Gauge wheel
c) Jointer
d) Land wheel
Discussion
Explanation: Jointer is a small irregular piece of metal having of a shape similar to an ordinary plough bottom. It looks like a miniature plough. The small furrow slice that is cut from left and upper side of the main furrow slice and is inverted so that all trashes on the top of the soil are completely turned down and buried under the right-hand corner of the furrow.