For the given figure, the brake can sustain a torque of 350 N-m and coefficient of friction between the band and drum is 0.3, find OA for self locking condition during clockwise rotation.

For the given figure, the brake can sustain a torque of 350 N-m and coefficient of friction between the band and drum is 0.3, find necessary force required for clockwise rotation of the drum in N.

A

32

B

64

C

96

D

128

For the given figure, the brake can sustain a torque of 350 N-m and coefficient of friction between the band and drum is 0.3, If the drum rotates in anticlockwise direction, find force in N.

A

804

B

756

C

850

D

900

What is the braking torque at leading shoe if resultant frictional force acts at a distance of 250 mm from the brake drum center, coefficient of friction between the shoe and the drum as 0.5, the free ends of the two shoes are pushed apart with a force of 300 N which is acting at a distance of 320 mm from anchor, and two shoes are anchored together 170 mm away from the brake drum center?

A

276.6 Nm

B

256.6 Nm

C

266.6 Nm

D

246.6 Nm

Drum X is 1/2 full of oil and drum Y, which has twice the capacity of drum X, is 2/3 full of oil. If all of the oil in drum X is poured into drum Y, then drum Y will be filled to what fraction of its capacity?

A

3/4

B

5/6

C

11/12

D

7/6

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

$$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = {\left( {\frac{{1 + \mu \tan \theta }}{{1 - \mu \tan \theta }}} \right)^{\text{n}}}$$

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

$$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = {\left( {\frac{{1 + \mu \tan \theta }}{{1 - \mu \tan \theta }}} \right)^{\text{n}}}$$

A pivoted double block brake has a drum radius of 280mm with two shoes subtending an angle of 100⁰. Maximum pressure intensity is 0.5N/mm². If the width of friction lining is 90mm, find the torque capacity f each shoe. Assume coefficient of friction as 0.2.

A

789N-m

B

1081N-m

C

945N-m

D

None of the listed

As the car slows down, the brake shoe and steel drum continuously absorbs 25 W. Assume a total outside surface area of 0.1 m2 with a convective heat transfer coefficient of 10 W/Km2 to the air at 20°C. How hot does the outside brake and drum surface become when steady conditions are reached?

A

25°C

B

35°C

C

45°C

D

55°C

A haulage rope winds on a drum of radius 500 mm, the free end being attached to a truck. The truck has a mass of 500 kg and is initially at rest. The drum is equivalent to a mass of 1250 kg with radius of gyration 450 mm. The rim speed of the drum is 0.75 m/s before the rope tightens. By considering the change in linear momentum of the truck and in the angular momentum of the drum, find the speed of the truck when the motion becomes steady.

A

0.502 m/s

B

0.602 m/s

C

0.702 m/s

D

0.802 m/s

The brake shown in figure has a coefficient of friction 0.25 and is to operate using a maximum force F of 500 N. Assume width of the band to be 50 mm. Find the maximum band tension. All dimensions are in mm.

A

4449.6 N

B

4440.8 N

C

5432.4 N

D

4882.3 N

For the given figure, the brake can sustain a torque of 350 N-m and coefficient of friction between the band and drum is 0.3, find OA for self locking condition during clockwise rotation.

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