A thin circular disc is rolling with a uniform linear speed, along a straight path on a plane surface. Which of the following statement is correct in this regard?
All points of the disc have the same velocity
The centre of the disc has zero acceleration
The centre of the disc has centrifugal acceleration
The point on the disc making contact with the plane surface has zero acceleration
Correct Answer :
B. The centre of the disc has zero acceleration
Related Questions
The frictional torque transmitted in a flat collar bearing, considering uniform wear, is (where r₁ and r₂ = External and internal radii of collar respectively)
(1/2) μ W (r₁ + r₂)
(2/3) μ W (r₁ + r₂)
(1/2) μ W [(r₁³ - r₂³)/(r₁² - r₂²)]
(2/3) μ W [(r₁³ - r₂³)/(r₁² - r₂²)]
The frequency of oscillation of a torsional pendulum is
2πk/r. √(g/l)
r/2πk. √(l/g)
2πr/k. √(g/l)
r/2πk. √(g/l)
The two links OA and OB are connected by a pin joint at O. If the link OA turns with angular velocity ω₁ rad/s in the clockwise direction and the link OB turns with angular velocity ω₂ rad/s in the anticlockwise direction, then the rubbing velocity at the pin joint O is (where r = Radius of the pin at O)
ω₁.ω₂.r
(ω₁ - ω₂) r
(ω₁ + ω₂) r
(ω₁ - ω₂) 2r
The two links OA and OB are connected by a pin joint at O. If the link OA turns with angular velocity ω₁ rad/s in the clockwise direction and the link OB turns with angular velocity ω₂ rad/s in the clockwise direction, then the rubbing velocity at the pin joint O is (where r = Radius of the pin at O)
ω₁.ω₂.r
(ω₁ - ω₂)r
(ω₁ + ω₂)r
(ω₁ - ω₂)2r
The direction of Coriolis component of acceleration is the direction
Of relative velocity vector for the two coincident points rotated by 90° in the direction of the angular velocity of the rotation of the link
Along the centripetal acceleration
Along tangential acceleration
Along perpendicular to angular velocity
The indicator using Watt mechanism is known as
Thompson indicator
Richard indicator
Simplex indicator
Thomson indicator
The secondary unbalanced force is maximum __________ in one revolution of the crank.
Two times
Four times
Eight times
Sixteen times
In a steam engine, the distance by which the outer edge of the Dslide valve overlaps the steam port is called
Lead
Steam lap
Exhaust lap
None of these
In a Hartnell governor, the compression of the spring is __________ the lift of the sleeve.
Equal to
Less than
Greater than
None of these
The relation between the controlling force (Fc) and radius of rotation (r) for a stable spring controlled governor is
Fc = ar + b
Fc = ar - b
Fc = ar
Fc = a/r + b
The velocity of the reciprocating roller follower when it has contact with the straight flanks of the tangent cam, is given by (where ω = Angular velocity of the cam shaft)
ω (r₁ r₂) sinθ
ω (r₁ + r₂) sinθ sec2θ
ω (r₁ r₂) cosθ
ω (r₁ + r₂) cosθ cosec2θ
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
Which of the following would constitute a link?
Piston, piston rod and cross head
Piston and piston rod
Piston rod and cross head
Piston, crank pin and crank shaft
Bifilar suspension method is used to find the
Angular acceleration of the body
Moment of inertia of the body
Periodic time of the body
Frequency of vibration of the body
In a four-bar chain it is required to give an oscillatory motion to the follower for a continuous rotation of the crank. For the lengths of 50 mm of crank and 70 mm of the follower, determine theoretical maximum length of coupler. The distance between fixed pivots of crank and followers is
95 mm
Slightly less than 95 mm
Slightly more than 95 mm
45 mm
In order to double the period of a simple pendulum, the length of the string should be
Halved
Doubled
Quadrupled
None of these
Which of the following statement is correct for gears?
The addendum is less than the dedendum
The pitch circle diameter is the product of module and number of teeth
The contact ratio means the number of pairs of teeth in contact
All of the above
The partial balancing means
Balancing partially revolving masses
Balancing partially reciprocating masses
Best balancing of engines
All of these
When there is a reduction in amplitude over every cycle of vibration, then the body is said to have
Free vibration
Forced vibration
Damped vibration
Under damped vibration
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
When a mass of a critically damped single degree of freedom system is deflected from its equilibrium position and released, then it will
Return to equilibrium position without oscillation
Oscillate with increasing time period
Oscillate with decreasing amplitude
Oscillate with constant amplitude
When the speed of the engine fluctuates continuously above and below the mean speed, the governor is said to be
Stable
Unstable
Isochronous
Hunt
Which gear is used for connecting two coplanar and intersecting shafts?
Spur gear
Helical gear
Bevel gear
None of the above
A disc is a spinning with an angular velocity ω rad/s about the axis of spin. The couple applied to the disc causing precession will be (where I = Mass moment of inertia of the disc, and ωP = Angular velocity of precession of the axis of spin)
(1/2).Iω²
Iω²
(1/2). I ω ωP
I ω ωP
In under damped vibrating system, if x₁ and x₂ are the successive values of the amplitude on the same side of the mean position, then the logarithmic decrement is equal to
x₁/x₂
log(x₁/x₂)
loge(x₁/x₂)
log(x₁.x₂)
If ω/ωn is very low for a body vibrating under steady state vibrations, the phase angle for all values of damping factors, will tend to approach
0°
90°
180°
360°
With single Hooke's joint it is possible to connect two shafts, the axes of which have an angular misalignment up to
10°
20°
30°
40°
If the radius of gyration of a compound pendulum about an axis through e.g. is more, then its frequency of oscillation will be
Less
More
Same
Data are insufficient to determine same
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
The moment on the pulley which produces rotation is called
Inertia
Momentum
Moment of momentum
Torque