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This set of Theory of Mechanics Multiple Choice Questions & Answers (MCQs) focuses on Theory Of Mechanics Set 5
Q1 | When moment due to friction force aids in applying the brake, it is called____.
- simple block brake
- pivoted block brake
- self-locking brake
- self-energized brake
Q2 | In a simple band brake, when direction of rotation of drum is changed from counter clockwise direction, the braking torque____.
- remains unchanged
- is increased
- is decreased
- is unpredictable
Q3 | In a differential band brake, the effort required for clockwise rotation of drum compared to counterclockwise rotation is____.
- greater
- equal
- less
- unpredictable
Q4 | Refer fig.3 pivot point O2, force at A acting vertically up, then ____.
- brake is equally effective in both the directions
- brake is more effective in counter-clockwise directions
- brake is more effective in clockwise directions
- brake is not effective in any direction
Q5 | Refer fig.3 pivot point O1, force at B acting vertically up, then ____.
- brake is equally effective in both the directions
- brake is more effective in counter-clockwise directions
- brake is more effective in clockwise directions
- brake is not effective in any direction
Q6 | Refer fig.3 Pivot point O3, force at A vertically up and if µ.d ≥ b then____.
- the brake is self-locking in clockwise direction
- the brake is self-locking in counter-clockwise direction
- the brake is self-locking in both the direction
- the brake is not self-locking in any direction
Q7 | Refer fig.3, The best choice for this brake is to have pivot point at____.
- o1
- o2
- o3
- anywhere between o3 and a.
Q8 | Refer fig.4. It shows a band brake arrangements. The brake to work with force at A upwards and direction of drum clockwise____.
- a=b
- a>b
- a
- independent of ratio (a/b)
Q9 | Refer Fig. 5 Force downwards and direction counter clockwise________
- system will work only if a is greater than b
- system will not work if a is less than b
- system will not work if a is equal to b
- all the above statements are correct
Q10 | Refer Fig. 5 Force downwards and direction counter clockwise________
- a/b=t1/t2 gives self-lock
- a=0 the brake still works
- b=0 the brake does not work
- all the above statements are correct
Q11 | The stopping distance for a vehicle by applying brakes when all the four wheels are sliding as compared to when all the four wheels are at impending slide is______
- more
- less
- same
- not predictable
Q12 | For the same co-efficient of friction between the road and the tier and assuming all the wheels at impending slip the stopping distance of vehicle from specified velocity on applying brakes
- increase with increase of the weight of vehicle
- decrease with increase of the weight of vehicle
- remains same irrespective of the weight of vehicle
- is unpredictable
Q13 | A vehicle has weight W and co-efficient of tractive co-efficient μr. It is moving with velocity V when brakes are applied, and all the wheels are at impending slip. The stopping distance Is x. If weight is increased by 50% and μr decreased by 50% then _______
- the stopping distance remains same
- the stopping distance increases by 50%
- the stopping distance decrease by 50%
- the stopping distance cannot be determined
Q14 | For same μr and all wheels are impending slip, stopping distance for four wheel vehicle is _____
- directly proportional to the velocity of vehicle
- directly proportional to square of the velocity of the vehicle
- directly proportional to weight of vehicle
- none of the above
Q15 | The stopping distance for four wheel vehicle is______
- unaltered by increase for four wheel vehicle
- decrease with increase of μr
- directly proportional to square of velocity of vehicle
- all the above
Q16 | Find the brake power of the engine running at 755 rpm. The length of lever from center of pulley is 1.43 m. The weight in pan is 40 kg.
- 40 kw
- 42.44 kw
- 44.36 kw
- 45.41 kw
Q17 | In a band brake the ratio of tight side band tension to the tension on the slack side is 3. If the angle of band on the drum is 1800 the coefficient of friction required between drum and band is_____
- 0.2
- 0.25
- 0.3
- 0.35
Q18 | A single block brake as shown in Fig.6 has a brake drum diameter of 1m and the angle of contact is 300. It takes 280 Nm torque at 300rpm. The coefficient of friction is 0.35. Determine the required force 'P' to be applied when the rotation of drum is clockwise.
- 378.99 n
- 420.99 n
- 435.45 n
- 450.38 n
Q19 | For above question determine the required force 'P' to be applied when the rotation of drum is anticlockwise.
- 378.99 n
- 420.99 n
- 435.45 n
- 450.38 n
Q20 | A bicycle and rider is mass 125 kg are travelling at speed of 10km/hr. The rider applies a break to the near wheel of 1 m diameter. How far the bicycle will travel before it comes to rest? The pressure applied to the brake is 120 N and μ = 0.05. Also find the number of revolutions made by bicycle before coming to rest.
- 24.58
- 25.58
- 23.79
- 35.48
Q21 | In a simple band brake applied to a shaft carrying a flywheel of mass 250kg and radius of gyration 350mm , one end of the band is attached to the fulcrum and the other at a distance 300 mm from the fulcrum. The angle embraced by the band is 2250 and the brake drum diameter is 220 mm coefficient of friction 0.25 and the shaft speed is 300 rpm clockwise. Determine the brake torque when a force of 150 N is applied
- 102.99 n
- 105.24 n
- 103.26 n
- 195.38 n
Q22 | A dynamometer is a device used for measuring
- power developed by a machine
- torque developed by a machine
- power absorbed by a machine
- all the above
Q23 | Dynamometer is a device for measuring ____
- torque exerted by the machine
- power developed by the machine
- power absorbed by the machine
- all of the above
Q24 | Which of the following is classified a absorption type of dynamometer?
- prony brake dynamometer
- rope brake dynamometer
- hydraulic dynamometer
- all of the above
Q25 | Which of the following is classified as transmission type of dynamometer?
- prony brake dynamometer
- rope brake dynamometer
- hydraulic dynamometer
- epicyclic dynamometer