Questions and answers for exam Preparation

MCQs

Total Questions : 2607 | Page 84 of 261 pages

When a hole of diameter 'd' is punched in a metal of thickness 't', then the force required to punch a hole is equal to (where`tau_u` = Ultimate shear strength of the material of the plat

`d.t.tau_u`
`pi d.t.tau_u`
`pi/4 xx d^2 tau_u`
`pi/4 xx d^2 xx t tau_u`

Discuss Question

Answer: Option B. -> `pi d.t.tau_u`

Question 832.
The relation between the pitch of the chain (p) and pitch circle diameter of the sprocket (D) is given by (where T = Number of teeth on the sprocket)

`P = D sin (90^circ/T)`
`P = D sin (120^circ/T)`
`P = D sin (180^circ/T)`
`P = D sin (360^circ/T)`

Discuss Question

Answer: Option C. -> `P = D sin (180^circ/T)`

Question 833.

For a shoe
brake, the equivalent coefficient of friction is equal to (where `mu` =
Actual coefficient of friction, and `theta` = Semi-block angle)

`(2 mu sin theta)/(theta + sin theta)`
`( mu sin theta)/(2theta + sin2 theta)`
`(4 mu sin theta)/(theta + sin theta)`
`(4 mu sin theta)/(2theta + sin2 theta)`

Discuss Question

Answer: Option D. -> `(4 mu sin theta)/(2theta + sin2 theta)`

Question 834.
In a band and block brake, the ratio of tensions on the tight and slack
sides of band is given by (where `mu` = Coefficient of friction between the
blocks and the drum, `theta`= Semi-angle of each block subtending at the
centre of drum, and n = Number of blocks)

`T_1/T_2 = mu theta xx n`
`T_1/T_2 =( mu theta )^n`
`T_1/T_2 =( (1 - mu tan theta)/(1 + mu tan theta))^n`
`T_1/T_2 =( (1 + mu tan theta)/(1 - mu tan theta))^n`

Discuss Question

Answer: Option D. -> `T_1/T_2 =( (1 + mu tan theta)/(1 - mu tan theta))^n`

Question 835.

The maximum efficiency of a square threaded screw is

`(1 - sin phi)/(1+ sin phi )`
`(1+ sin phi)/(1- sin phi )`
`(1 -cos phi)/(1+ cos phi )`
`(1 +cos phi)/(1-cos phi )`

Discuss Question

Answer: Option A. -> `(1 - sin phi)/(1+ sin phi )`

Question 836.

Lewis form factor for` 14 1^circ/2` composite and full depth involute system is (where T = Number of teeth)

`0.124 - 0.684/T`
`0.154 - 0.912/T`
`0.175 - 0.841/T`
none of these

Discuss Question

Answer: Option A. -> `0.124 - 0.684/T`

Question 837.
According to Lame's equation, the thickness of a cylinder is equal to (where d = Inner diameter of cylinder, p = Internal pressure, and `mu`= Poisson's ratio. )

`d/2 [ sqrt(sigma_t + (1 - 2mu) p)/(sigma_t - (1 + mu)p) - 1]`
`d/2 [ sqrt(sigma_t + (1 - mu) p)/(sigma_t - (1 + mu)p) - 1]`
`d/2 [ sqrt(sigma_t + p)/(sigma_t - P) - 1]`
none of these

Discuss Question

Answer: Option C. -> `d/2 [ sqrt(sigma_t + p)/(sigma_t - P) - 1]`

Question 838.

When an open coiled helical compression spring is subjected to an axial load (W), the compression produced in the spring will be (where n = No. of active turns of the spring, and G = Modulus of rigidity for the spring material)

`(2WD^3 n)/(Gd^4)`
`(4WD^3 n)/(Gd^4)`
`(8WD^3 n)/(Gd^4)`
`(16WD^3 n)/(Gd^4)`

Discuss Question

Answer: Option C. -> `(8WD^3 n)/(Gd^4)`

Question 839.
The velocity factor for precision metallic gears cut with high accuracy and operating at velocities upto 20 m/s is equal to

`(0.75)/(0.75 + sqrt(V))`
`(3)/(3+ V)`
`(4.5)/(4.5+ V)`
`(6)/(6+ V)`

Discuss Question

Answer: Option A. -> `(0.75)/(0.75 + sqrt(V))`

Question 840.

When an open
coiled helical compression spring is subjected to an axial compressive
load, the maximum shear stress induced in the wire is (where D = Mean diameter of the spring coil, d = Diameter of the spring wire, K = Wahl's stress factor, and W = Axial compressive load on the spring)