SSC · Theory of Machines practice

Correct answer: B

Using Gruebler’s equation F = 3(n − 1) − 2j − h = 3 × 3 − 2 × 4 − 0 = 1.

Correct answer: B

It absorbs energy when the speed rises and gives it back when the speed falls. A governor controls the mean speed.

Correct answer: C

It adjusts the fuel supply to the engine in response to load changes.

Correct answer: C

m = d/z = 120/40 = 3 mm.

Correct answer: D

14.5° was used earlier but 20° full-depth teeth are now standard because they are stronger and avoid interference with fewer teeth.

Correct answer: C

T1/T2 = e^(μθ), where θ is the angle of contact in radians.

Correct answer: C

Static balance needs ΣF = 0. Dynamic balance also needs the resultant couple to be zero.

Correct answer: B

ωn = √(k/m) = √(3600/4) = √900 = 30 rad/s.

Correct answer: A

The follower is at its lowest position when it touches the base circle.

Correct answer: D

A universal joint transmits motion between intersecting shafts, though the speed of the driven shaft fluctuates.

Correct answer: C

N2 = N1 × (T1/T2) = 600 × 20/60 = 200 rpm.

Correct answer: C

It does not alter the velocity ratio, as the idler’s tooth count cancels out.

Correct answer: C

The component is 2ωv, perpendicular to the sliding velocity, and arises in quick-return mechanisms and similar linkages.

Correct answer: A

Cs = (N1 − N2) / Nmean = 20 / 300 = 0.067.

Correct answer: D

From P = (T − Tc)(1 − e^(−μθ))v, dP/dv = 0 gives Tc = T/3.

Correct answer: B

At ζ = 1 the system returns to equilibrium in the shortest time without oscillating.

Correct answer: D

The primary force is m r ω² cos θ, whose peak occurs at θ = 0° and 180°.

Correct answer: A

C = I ω ωp = 0.5 × 100 × 2 = 100 N·m.

Correct answer: D

The sudden jump in velocity requires an infinite acceleration, which causes impact. Modified profiles round off the ends.

Correct answer: C

N = n(n − 1)/2 = 6 × 5 / 2 = 15.