1. In which rivet joint the plates are kept in the same plane?
a) Lap joint
b) Wood screws
c) Butt joints
d) Cap screws
Discussion
Explanation: Rivets are used for connecting two pieces of metal plates or bars permanently. In butt joints, the plates are kept in the same plane and the joint is covered on one or both sides by a cover plate which is riveted to the plates.
2. What is the train value (G) in compound gear train?
a) G = \(\frac{N6}{N1} = \frac{T1*T2*T3}{T2*T4*T6} \)
b) G = N6 * N1 = T1+T2+T3+T4+T6
c) G = N6 – N1 = T1 * T2 * T3 * T4 * T6
d) G = \(\frac{N1}{N6} = \frac{T2*T4*T6}{T1*T2*T3} \)
Discussion
Explanation: A system of gears which transmits motion from one shaft to another is known as a gear train. When there is more than one gear on a shaft, then, it is called a compound train of gear.
3. What is the length of cross belt to connect two pulleys 4 m apart. the diameter of driving and driven pulley is 1.25 m and 0.75m respectively?
a) 12.39m
b) 11.39m
c) 13.39m
d) 10.39m
Discussion
Explanation: Lc = 2x + \(\frac{π}{2}\)(d1+d2)+\(\frac{(d1+d2)^2}{4x} \)
= 2*4 + \(\frac{π}{2}\)(1.25+0.75) + \(\frac{(1.25+0.75)^2}{4*4} \)
= 11.39m.
4. Which of the following is not a type of chain?
a) Roller
b) Hook link
c) Pintle
d) Bevel
Discussion
Explanation: Bevel is a type of gear used where the axis of the two shafts are at right angles and can intersect each other. When the power has to turn a corner, bevel gears are used. Plain bevel gears have straight teeth while spiral bevel gears have twisted teeth.
5. Which of the following is not a type of screw?
a) Machine
b) Hexagonal
c) Square
d) Plough
Discussion
Explanation: Machines are a type of screws which are threaded for their full length. They look like bolts. They are used to screw directly into threaded holes in machine part and do not need nuts.
6. What is the width of belt to transmit 15 HP to a pulley 35 cm in diameter. Pulley makes 1600 rev/min, coefficient of friction between belt is 0.22 and angle of contact is 20°. Maximum tension in belt not to exceed 8 kg per cm width.
a) 7.79cm
b) 9.79cm
c) 3.49cm
d) 8.79cm
Discussion
Explanation: \(\frac{T1}{T2}\) = e0.22*3.66=e0.8065
T1 = T2 * 2.24
15*746 = \(\frac{[π*35*1600(T1-T2)]}{100*60} \)
2.24 T2-T1 = 381.63
T2 = \(\frac{381.63}{1.24}\) = 307.76N
T1 = 307.76*2.24=689.38N
Width of the belt = \(\frac{689.38}{8*9.8}\) = 8.79cm.
7. In a belt drive the mass of the belt is 1 kg/m and its speed is 6m/s. The drive transmits 9.6 KW of power. Determine the strength of the belt when the coefficient of friction is 0.25 and wrap angle is 220°.
a) 2629.78 N
b) 2404.73 N
c) 2003.09 N
d) 1829.78 N
Discussion
Explanation: Tc = mv2 = 1*62 = 36 N
\(\frac{T1}{T2}\)=eμθ
\(\frac{T1}{T2}=e^{0.25*220*\frac{\pi}{180}}\) = 2.6102
P = (T1-T2) * V
9.6*103 = (T1-T2) * 6
T1-T2 = 1600
T1 = 2593.78 N
T2 = 993.78 N
Strength = T1 + Tc = 2629.78 N
8. What power is transmitted by belt and pulley arrangement, if tension on tight side of belt is 60 kg and tension on slack side is 25kg. The diameter and speed of driving pulley is 0.95 m and 250 rpm respectively.
a) 5.239 KW
b) 9.624 KW
c) 2.264 KW
d) 4.269 KW
Discussion
Explanation: peripheral velocity = \(\frac{πDN}{60}=\frac{π*0.95*250}{60}\) = 12.4354 m/s
P = (T1-T2) * V
P = (60-25) * 9.81 * 12.4354 = 4.269 KW
9. A counter shaft of engineering workshop is being driven by electric motor with the help of canvas belt and pulley arrangement such that the speed of belt is 600 m/min and it transmits 50 KW. What will be the difference between tensions on either side of the belt?
a) 10000
b) 100
c) 5000
d) 50
Discussion
Explanation: V = 600*10/60 = 10 m/s
P = (T1-T2) * V
50000 = (T1-T2) * 10
T1 – T2 = 5000
10. If a driven pulley is made to rotate at 350 rpm by a driving pulley of 0.3 m diameter, running at 1400 rpm, what will be the length of open belt drive when the pulleys are 2 m apart?
a) 7.14 m
b) 6.45 m
c) 8.88 m
d) 10 m
Discussion
Explanation: N1D1 = N2D2
1400 * 0.3 = 350 * D2
D2 = 1.2 m
Length of open belt drive = 2C + \(\frac{[π(D1+D2)]}{2}+\frac{(D1-D2)^2}{4C} \)
= 2*2 + \(\frac{[π(1.5)]}{2}+\frac{(0.9)^2}{8} \)
= 6.45 m