In involute gears, the pressure angle is
Dependent on the size of teeth
Dependent on the size of gears
Always constant
Always variable
Correct Answer :
C. Always constant
Related Questions
Length of arc of contact is given by
Arc of approach - Arc of recess
Arc of approach + Arc of recess
Arc of approach / Arc of recess
Arc of approach × Arc of recess
When the sleeve of a Porter governor moves upwards, the governor speed
Increases
Decreases
Remain unaffected
First increases and then decreases
Hammer blow
Is the maximum horizontal unbalanced force caused by the mass provided to balance the reciprocating masses.
Is the maximum vertical unbalanced force caused by the mass added to balance the reciprocating masses
Varies as the square root of the speed
Varies inversely with the square of the speed
Which of the following disciplines provides study of the relative motion between the parts of a machine and the forces acting on the parts?
Theory of machines
Applied mechanics
Mechanisms
Kinetics
In a rigid link OA, velocity of A w.r.t. O will be
Parallel to OA
Perpendicular to OA
At 45° to OA
Along AO
If ω/ωn = 2, where co is the frequency of excitation and ωn is the natural frequency of vibrations, then the transmissibility of vibration will the
0.5
1
1.5
2
When the pitching of a ship is upward, the effect of gyroscopic couple acting on it will be
To move the ship towards starboard
To move the ship towards port side
To raise the bow and lower the stern
To raise the stern and lower the bow
The acceleration of a flat-faced follower when it has contact with the flank of a circular arc cam, is given by
ω² R cosθ
ω² (R - r₁) cosθ
ω² (R - r₁) sinθ
ω² r₁ sinθ
The size of cam depends upon
Base circle
Pitch circle
Prime circle
Pitch curve
The cam follower generally used in automobile engines is
Knife edge follower
Flat faced follower
Spherical faced follower
Roller follower
The coriolis component of acceleration is taken into account for
Slider crank mechanism
Four bar chain mechanism
Quick return motion mechanism
All of these
A simple spring-mass vibrating system has a natural frequency of fn. If the spring stiffness is halved and the mass is doubled, then the natural frequency will become
fn/2
2 fn
4 fn
8 fn
The unbalanced primary forces in a reciprocating engine are
Balanced completely
Balanced partially
Balanced by secondary forces
Not balanced
A reed type tachometer use the principle of
Longitudinal vibration
Torsional vibration
Transverse vibration
Damped free vibration
Transmission angle is the angle between
Input link and coupler
Input link and fixed link
Output link and coupler
Output link and fixed link
A spring controlled governor is found unstable. It can be made stable by
Increasing the spring stiffness
Decreasing the spring stiffness
Increasing the ball mass
Decreasing the ball mass
Crowning on pulleys helps
In increasing velocity ratio
In decreasing the slip of the belt
For automatic adjustment of belt position so that belt runs centrally
Increase belt and pulley life
The ratio of maximum fluctuation of energy to the workdone per cycle is called
Fluctuation of energy
Maximum fluctuation of energy
Coefficient of fluctuation of energy
None of these
An automobile steering gear is an example of
Sliding pair
Rolling pair
Lower pair
Higher pair
The primary unbalanced force is maximum _________ in one revolution of the crank.
Twice
Four times
Eight times
Sixteen times
The secondary unbalanced force is maximum __________ in one revolution of the crank.
Two times
Four times
Eight times
Sixteen times
The factional torque for square thread at the mean radius r while raising load W is given by
T = W.r tan(φ - α)
T = W.r tan(φ + α)
T = W.r tanα
T = W.r tanφ
In order to facilitate starting of locomotive in any position, the cranks of a locomotive with two cylinders, are placed at
45° to each other
90° to each other
120° to each other
180° to each other
There are six gears A, B, C, D, E and F in a compound train. The numbers of teeth in the gears are 20, 60, 30, 80, 25 and 75 respectively. The ratio of angular speeds of the driven (F) to the driver (A) of the drive is
1/24
1/8
4/15
12
When a slider moves on a fixed link having curved surface, their instantaneous centre lies
On their point of contact
At the centre of curvature
At the centre of circle
At the pin joint
The efficiency of a screw jack is maximum, when (where α = Helix angle, and φ = Angle of friction)
α = 45° + φ/2
α = 45° - φ/2
α = 90° + φ
α = 90° - φ
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
Which of the following is an inversion of Single slider crank chain?
Beam engine
Rotary engine
Oldhams coupling
Elliptical trammel
The frequency of oscillation at compared to earth will be
6 times more
6 times less
2.44 times more
2.44 times less
A universal joint is an example of
Higher pair
Lower pair
Rolling pair
Sliding pair