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

A $$\frac{{2\mu \sin \theta }}{{\theta + \sin \theta }}$$
B $$\frac{{\mu \sin \theta }}{{2\theta + \sin 2\theta }}$$
C $$\frac{{4\mu \sin \theta }}{{\theta + \sin \theta }}$$
D $$\frac{{4\mu \sin \theta }}{{2\theta + \sin 2\theta }}$$

Correct Answer: $$\frac{{4\mu \sin \theta }}{{2\theta + \sin 2\theta }}$$

Bissoy MCQ
#Mechanical Engineering #Machine Design

Related Questions

In a band and block brake, the ratio of tensions on tight side and slack side of the band is (where $$\mu $$ = Coefficient of friction between the blocks and the drum, $$\theta $$ = Semi-angle of each block subtending at the center of drum and n = Number of blocks)
A $$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = \mu \theta {\text{n}}$$
B $$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = {\left( {\frac{{1 - \mu \tan \theta }}{{1 + \mu \tan \theta }}} \right)^{\text{n}}}$$
C $$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = {\left( {\mu \theta } \right)^{\text{n}}}$$
D $$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = {\left( {\frac{{1 + \mu \tan \theta }}{{1 - \mu \tan \theta }}} \right)^{\text{n}}}$$
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)
A $$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_{\text{2}}}}} = \mu \theta \times {\text{n}}$$
B $$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = {\left( {\mu \theta } \right)^{\text{n}}}$$
C $$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = {\left( {\frac{{1 - \mu \tan \theta }}{{1 + \mu \tan \theta }}} \right)^{\text{n}}}$$
D $$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = {\left( {\frac{{1 + \mu \tan \theta }}{{1 - \mu \tan \theta }}} \right)^{\text{n}}}$$
During braking, the brake shoe is moved outward to force the lining against the
A Wheel piston or cylinder
B Anchor pin
C Brake drum
D Wheel rim or axle
The maximum efficiency of spiral gears is (where $$\theta $$ = Shaft angle and $$\varphi $$ = Friction angle)
A $$\frac{{\sin \left( {\theta + \varphi } \right) + 1}}{{\cos \left( {\theta - \varphi } \right) + 1}}$$
B $$\frac{{\cos \left( {\theta - \varphi } \right) + 1}}{{\sin \left( {\theta + \varphi } \right) + 1}}$$
C $$\frac{{\cos \left( {\theta + \varphi } \right) + 1}}{{\cos \left( {\theta - \varphi } \right) + 1}}$$
D $$\frac{{\cos \left( {\theta - \varphi } \right) + 1}}{{\cos \left( {\theta + \varphi } \right) + 1}}$$
For a bevel gear having the pitch angle $$\theta $$, the ratio of formative number of teeth (TE) to actual number of teeth (T) is
A $$\frac{1}{{\sin \theta }}$$
B $$\frac{1}{{\cos \theta }}$$
C $$\frac{1}{{\tan \theta }}$$
D $$\sin \theta \cos \theta $$
The sequence in which the force is transmitted through a brake system when the brake pedal is depressed is
A Brake pedal, Master cylinder, Brake lines, Vacuum servo mechanism, Brake pads
B Brake pedal, Vacuum servo mechanism, Master cylinder, Brake lines, Brake pads
C Brake pedal, Master cylinder, Vacuum servo mechanism, Brake lines, Brake pads
D Brake pedal, Brake lines, Vacuum servo mechanism, Master cylinder, Brake pads
In recent times, the “dynamic brake system” is becoming popular in modern railways. The dynamic brake system coverts Kinetic energy to________:
A Potential energy
B Electricity
C Sound energy
D Magnetic energy
The material used for brake lining should have __________ coefficient of friction.
A Low
B High
C Moderate
D None of these
A Thevenin ac equivalent circuit always consists of an equivalent ac voltage source and an equivalent capacitance.
A True
B False
Norton's theorem provides a method for the reduction of any ac circuit to an equivalent form consisting of an equivalent voltage source in series with an equivalent impedance.
A True
B False

Next steps