# MCQs on Keys

1 - Question

A force 2P is acting on the double transverse fillet weld. Leg of weld is h and length l. Determine the shear stress in a plane inclined at θ with horizontal.

a) PSinθ(Sinθ+Cosθ)/hl
b) P(Sinθ+Cosθ)/hl
c) Pcosθ(Sinθ+Cosθ)/hl
d) None of the listed

Explanation: F=PSinθ and width=h/(Sinθ+Cosθ).

2 - Question

Maximum shear stress in transverse fillet weld of leg h and length l is

a) P/hl
b) 1.21P/hl
c) P/1.21hl
d) None of the listed

Explanation: τ= PSinθ(Sinθ+Cosθ)/hl, by maximising it θ=67.5’ and hence find corresponding τ.v

3 - Question

A sunk key fits in the keyway of the _____ only.

a) Hub
b) Sleeve
c) Both hub and sleeve
d) Neither hub nor sleeve

Explanation: Sunk key fits halfway in the hub and halfway in the shaft.

4 - Question

Hollow saddle key is superior to flat saddle key as far as power transmitting capability is concerned.

a) True
b) False

Explanation: The resistance to slip in case of flat key is more.

5 - Question

Saddle key is more suitable than sunk key for heavy duty applications.

a) True
b) False

Explanation: In sunk key, relative motion is also prevented by shear resistance of sunk key and hence sunk key is recommended.

6 - Question

The main advantage of sunk key is that it is a _____ drive.

a) Positive
b) Negative
c) Neutral
d) None of the listed

Explanation: Sunk key is a positive drive and no slip occurs.

7 - Question

Woodruff key permits _____ movement b/w shaft and the hub.

a) Axial
c) Eccentric
d) None of the listed

Explanation: Woodruff key is a sunk key and doesn’t permit axial moment.

8 - Question

Determine the length of kennedy key required to transmit 1200N-m and allowable shear in the key is 40N/mm². The diameter of shaft and width of key can be taken as 40mm and 10mm respectively.

a) 49mm
b) 36mm
c) 46mm
d) 53mm

Explanation: l=M/[dbτ√2].

9 - Question

Splines are keys.
a) True b) False

Explanation: Splines are keys made with shafts.

10 - Question

Involute splines have stub teeth with a pressure angle of ___

a) 30
b) 45
c) 60
d) Can’t be determined