# Mechanical Engineering Past Papers MCQs

Mechanical Engineering Past Papers MCQs

select the belt length when the diameter of the two pulleys are 550mm and 300mm if the centre distance is 2800mm.
(A).  6.5m
(B).  6.94m
(C).  4.66m
(D).  5.26m
(E). None of these

(E). None of these

Select about the following statement, Crowns are never mounted on the pulley.
(A).  False
(B).  True

(E). None of these

In a cast-iron pulley minor axis is mostly retained in the plane of rotation.
(A).  False
(B).  True

(E). None of these

Band brake has a compound building with a large number of parts.
(A).  Yes
(B).  It has complicated construction but a small number of parts
(C).  It has simple constructions but a large number of parts
(D).  It has a simple construction

(E). None of these

Answer: (D).  It has a simple construction

Select the toughness of a material, when it is heated.

A. decreases
B. increases
C. does not change
D. both a and b
(E). None of these

Disk brakes mostly face the problem of self-locking.
(A).  Yes
(B).  Self-locking but it depends on the radius of the wheel rotating
(C).  No
(D).  Material dependent

(E). None of these

Disk brakes can be used for reverse rotation of the disk is also.
(A).  Poor efficiency in the opposite direction
(B).  They can be used
(C).  No they are effective for one direction of motion only

(D).  None of the listed
(E). None of these

(E). None of these

Answer: (C).  No they are effective for one direction of motion only

Select the sliding bearing in which the working surfaces are totally break up from each other by lubricant is known as zero film bearing.

A. False
B. True
(E). None of these

Select the number of slots in a 25 mm castle nut.

A. 6
B. 4
C. 2
D. 8
(E). None of these

at least one end of the band passes through the fulcrum, when we talk about both simple band brake and differential band brake,
(A).  Both the ends
(B).  One end
(C).  Neither end
(D).  All of the above
(E). None of these

(E). None of these

When the maximum tension in the belt is 900N and the allowable belt load is 500N. compute the number of belts needed to transmit power.
(A).  4
(B).  3
(C).  2
(D).  5

(E). None of these

The belt tension is maximum if the velocity of the belt is 0.
(A).  It has a constant value
(B).  True
(C).  It is velocity independent
(D).  It maxes at v=infinity

(E). None of these

Answer: (D).  It maxes at v=infinity

Can we prevent back rotation of the drum?
(A).  Depends on the angular velocity
(B).  No
(C).  Yes by using back stop brake
(D).  Only in some specific cases
(E). None of these

(E). None of these

Answer: (C).  Yes by using bac kstop brake

we can say that the self-locking differential brake and back stop brakes are the same thing.
(A).  False
(B).  True

(E). None of these

The wear of band brake is even?
(A).  False
(B).  True

(E). None of these

Select the braking torque if the tension in the two sides is 3500N and 1980N with a radius of drum being 160mm.
(A).  None of the mentioned
(B).  278.6N-m
(C).  223.4N-m
(D).  243.20N-m

(E). None of these

The Disk brakes have short torque transmitting capacity in high volumes.
(A).  False
(B).  True
(E). None of these

(E). None of these

When the temperature grow coefficient of friction__________ In drum brakes,
(A).  increases
(B).  Can’t be determined
(C).  remains the same
(D).  decreases

(E). None of these

The term of Loss of torque transmitting capacity at high temperatures is known as
(A).  Drifting
(B).  Rolling
(D).  Planking

(E). None of these

The pitch diameter of bigger pulley D in terms of small diameter d is defined through
(A).  dx[speed of bigger pulley/speed of smaller pulley]
(B).  dx[speed of smaller pulley/speed of bigger pulley]
(C).  d
(D).  None of these

(E). None of these

Answer: (B).  dx[speed of smaller pulley/speed of bigger pulley]

The Band brakes need which type of maintenance.
(A).  Much
(B).  Zero
(C).  Little
(D).  none of the above

(E). None of these

Screws used for power transmission should have

A. Low efficiency
B. high efficiency
D. strong teeth
(E). None of these

Select the number of rivets in shear shall same as to the number of rivets in crushing.

A. False
B. True
(E). None of these

The disk brake torque is linearly proportional to the operating force.
(A).  Independent of force
(B).  No, it is proportional to its square
(C).  Proportional to its cube
(D).  Yes

(E). None of these

The sleeve or muff coupling is formed as

A. hollow shaft
B. thick cylinder
C. solid shaft
D. dun cylinder
(E). None of these

When the tensions in the belt are P₁ and P₂, then find P₁-mv²/P₂-mv². The contact angle for smaller pulley is 156⁰, Groove angle is 36⁰ and coefficient of friction is 0.2.
(A).  6.21
(B).  4.66
(C).  5.83
(D).  5.36

(E). None of these

compute the angle of the wrap when the diameter of the two pulleys are 550mm and 300mm, and centre distance is 2800mm.
(A).  159.3⁰
(B).  167.8⁰
(C).  174.8⁰
(D).  None of the mentioned

(E). None of these

compute the arc of contact when the diameter of the two pulleys are 550mm and 300mm, and centre distance is 2800mm.
(A).  1.02
(B).  1.03
(C).  1.01
(D).  1.04

(E). None of these Prof.Fazal Rehman Shamil (Available for Professional Discussions)