4

# A Hartnell governor has its controlling force (Fc) given by Fc = ar + b, where r is the radius of rotation and a and b are constants. The governor becomes isochronous when

a is +ve and b = 0

a = 0 and b is +ve

a is +ve and b is -ve

a is +ve and b is also +ve

A. a is +ve and b = 0

4

Fc = ar + b

Fc = ar - b

Fc = ar

Fc = a/r + b

4

α = 45° + φ/2

α = 45° - φ/2

α = 90° + φ

α = 90° - φ

4

12

16

25

32

4

Maximum

Minimum

Zero

None of these

4

# Sense of tangential acceleration of a link

Is same as that of velocity

Is opposite to that of velocity

Could be either same or opposite to velocity

Is perpendicular to that of velocity

4

# The contact ratio is the ratio of

Length of pair of contact to the circular pitch

Length of arc of contact to the circular pitch

Length of arc of approach to the circular pitch

Length of arc of recess to the circular pitch

4

Is in phase

Lags by 90°

4

# The face of the tooth is the

Surface of the top of tooth

Surface of tooth above the pitch surface

Width of tooth below the pitch surface

Width of tooth measured along the pitch circle

4

# Coriolis component acts

Perpendicular to sliding surfaces

Along sliding surfaces

Somewhere in between above two

None of the above

4

# When a point moves along a straight line, its acceleration will have

Tangential component only

Coriolis component only

4

Zero

Minimum

Maximum

None of these

4

# Klein's construction can be used when

Crank has a uniform angular velocity

Crank has non-uniform velocity

Crank has uniform angular acceleration

Crank has uniform angular velocity and angular acceleration

4

3 Hz

3π Hz

6 Hz

6π Hz

4

Structure

Mechanism

Inversion

Machine

4

Base circle

Pitch circle

Prime circle

Pitch curve

4

# In a cam drive with uniform velocity follower, the sharp corners of the displacement diagram are rounded off at the beginning and at the end of each stroke. This is done

Because of difficulty in manufacturing cam profile

Because of loose contact of follower with cam surface

In order to have acceleration in beginning and retardation at the end of stroke within the finite limits

Because the uniform velocity motion is a partial parabolic motion

4

# The Ackermann steering mechanism is preferred to the Davis type in automobiles because

The former is mathematically accurate

The former is having turning pair

The former is most economical

The former is most rigid

4

# The coriolis component of acceleration exists whenever a point moves along a path that has

Linear displacement

Rotational motion

Gravitational acceleration

Tangential acceleration

4

# Which one of the following is an exact straight line mechanism using lower pairs?

Watts mechanism

Grasshopper mechanism

Roberts mechanism

Peaucelliers mechanism

4

# A spring controlled governor is said to be isochronous when the controlling force

Increases as the radius of rotation decreases

Increases as the radius of rotation increases

Decreases as the radius of rotation increases

Remain constant for all radii of rotation

4

1-3 m/s

3-15 m/s

15-30 m/s

30-50 m/s

4

(1/2).Iω²

Iω²

(1/2). I ω ωP

I ω ωP

4

# The maximum fluctuation of speed is the

Difference of minimum fluctuation of speed and the mean speed

Difference of the maximum and minimum speeds

Sum of maximum and minimum speeds

Variations of speed above and below the mean resisting torque line

4

l - 2

l - 1

l

l + 1

4

10°

20°

30°

40°

4

# In order to give a complete secondary balance of a multi-cylinder inline engine,

The algebraic sum of the secondary forces must be equal to zero

The algebraic sum of the couples about any point in the plane of the secondary forces must be equal to zero

Both (A) and (B)

None of these

4

# The instantaneous centres which vary with the configuration of mechanism are called

Permanent instantaneous centres

Fixed instantaneous centres

Neither fixed nor permanent instantaneous centres

None of the above

4

# Two pulleys of radii r₁ and r₂ and at distance x apart are connected by means of an open belt drive. The length of the belt is

π (r₁ + r₂) + (r₁ + r₂)²/x + 2x

π (r₁ + r₂) + (r₁ - r₂)²/x + 2x

π (r₁ - r₂) + (r₁ - r₂)²/x + 2x

π (r₁ - r₂) + (r₁ + r₂)²/x + 2x

4

# The danger of breakage and vibration is maximum

Below the critical speed

Near the critical speed

Above the critical speed

None of these