4

90°

180°

360°

A. 0°

4

# The brake commonly used in railway trains is

Shoe brake

Band brake

Band and block brake

Internal expanding brake

4

# The cam follower generally used in aircraft engines is

Knife edge follower

Flat faced follower

Spherical faced follower

Roller follower

4

Screw pair

Spherical pair

Turning pair

Sliding pair

4

ω/2π

2π/ω

ω × 2π

π/ω

4

1.4 N-s/m

18.52 N-s/m

52.92 N-s/m

529.2 N-s/m

4

# The displacement of a flat faced follower when it has contact with the flank of a circular arc cam, is given by (where R = Radius of flank, r₁ = Minimum radius of the cam, and θ = Angle turned through by the cam)

R (1 - cosθ)

(R - r₁) (1 - cosθ)

R (1 - sinθ)

(R - r₁) (1 - sinθ)

4

# The gear train usually employed in clocks is a

Simple gear train

Reverted gear train

Sun and planet gear

Differential gear

4

# When the load on the engine increases, it becomes necessary to increase the supply of working fluid and when the load decreases, less working fluid is required. The supply of the working fluid to the engine is controlled by a

D-slide valve

Governor

Meyer's expansion valve

Flywheel

4

Bevel gear

Universal joint

Hooke's joint

Knuckle joint

4

# Which of the following is false statement in respect of differences between machine and structure?

Machines transmit mechanical work, whereas structures transmit forces

In machines, relative motion exists between its members, whereas same does not exist in case of structures

Machines modify movement and work, whereas structures modify forces

Efficiency of machines as well as structures is below 100%

4

ω²r. (n + 1)/n

ω²r. (n - 1)/n

ω²r. n/(n + 1)

ω²r. n/(n - 1)

4

# The direction of linear velocity of any point on a link with respect to another point on the same link is

Parallel to the link joining the points

Perpendicular to the link joining the points

At 45° to the link joining the points

None of the above

4

# A governor is said to be stable, if the

Radius of rotation of balls increases as the equilibrium speed decreases

Radius of rotation of balls decreases as the equilibrium speed decreases

Radius of rotation of balls increases as the equilibrium speed increases

Radius of rotation of balls decreases as the equilibrium speed increases

4

Stable

Unstable

Isochronous

None of these

4

# The moment on the pulley which produces rotation is called

Inertia

Momentum

Moment of momentum

Torque

4

# The maximum frictional force, which comes into play, when a body just begins to slide over the surface of the other body, is known as

Static friction

Dynamic friction

Limiting friction

Coefficient of friction

4

# The displacement of the reciprocating roller follower, when it has contact with the straight flanks of the tangent cam, is given by (where r₁ = Minimum radius of the cam, r₂ = Radius of the roller follower, and θ = Angle turned by the cam from the beginning of the follower displacement)

(r₁ - r₂) (1 - cosθ)

(r₁ + r₂) (1 + cosθ)

(r₁ - r₂) [(1 - cosθ)/cos θ]

(r₁ + r₂) [(1 - cosθ)/cos θ]

4

Structure

Mechanism

Inversion

Machine

4

# A body of weight W is required to move up the rough inclined plane whose angle of inclination with the horizontal is α. The effort applied parallel to the plane is given by (where μ = tan φ = Coefficient of friction between the plane and the body)

P = W tan α

P = W tan (α + φ)

P = W (sin α + μ cos α)

P = W (cos α + μ sin α)

4

# Which of the following is a pendulum type governor?

Watt governor

Porter governor

Hartnell governor

None of these

4

# The example of successfully constrained motion is a

Motion of an I.C. engine valve

Motion of the shaft between a footstep bearing

Piston reciprocating inside an engine cylinder

All of the above

4

# If the rotating mass of a rim type flywheel is distributed on another rim type flywheel whose mean radius is half the mean radius of the former, then energy stored in the latter at the same speed will be

Four times the first one

Same as the first one

One fourth of the first one

One and a half times the first one

4

# A watt's governor can work satisfactorily at speeds from

60 to 80 r.p.m.

80 to 100 r.p.m.

100 to 200 r.p.m.

200 to 300 r.p.m.

4

# In locomotives, the ratio of the connecting rod length to me crank radius is kept very large in order to

Minimise the effect of primary forces

Minimise the effect of secondary forces

Have perfect balancing

To start the locomotive quickly

4

# When a body is subjected to transverse vibrations, the stress induced in a body will be

Shear stress

Bending stress

Tensile stress

Compressive stress

4

# A chain comprises of 5 links having 5 joints. Is it kinematic chain?

Yes

No

It is a marginal case

Data are insufficient to determine it

4

# The engine of an aeroplane rotates in clockwise direction when seen from the tail end and the aeroplane takes a turn to the left. The effect of gyroscopic couple on the aeroplane will be

To dip the nose and tail

To raise the nose and tail

To raise the nose and dip the tail

To dip the nose and raise the tail

4

α = 45° + φ/2

α = 45° - φ/2

α = 90° + φ

α = 90° - φ

4

# Kinematic pairs are those which have

Point or line contact between the two elements when in motion

Surface contact between the two elements when in motion

Elements of pairs not held together mechanically

Two elements that permit relative motion