Machine Design Multiple Choice Questions on “Brakes”.
1. The energy absorb by brake is always kinetic.
a) No, potential
b) Kinetic or potential
c) Potential
d) Strain Energy
Answer: b
Clarification: It can be either kinetic or potential.
2. Pneumatic brakes are same as electrical brakes.
a) Yes both are concerned with electricity
b) No, one deals with pressure and other with electricity
c) Yes both deals with pressure
d) None of the listed
Answer: b
Clarification: Pneumatic brakes are operated by fluid pressure.
3. Disc brakes are radial brakes.
a) True
b) False
Answer: b
Clarification: Disc brakes are axial brakes.
4. Internal shoe brakes are radial while external shoe brakes are axial brakes.
a) True
b) False
Answer: b
Clarification: Both internal and external shoe brakes are radial brakes.
5. A solid cast iron disk of mass 1000kg is rotating at 350rpm. Diameter of the disk is 1m and time taken to come to stop the disk by brake is 1.6sec.Calculate energy absorbed by the brake if square of radius of gyration is 0.2.
a) None of the mentioned
b) 134.3kJ
c) 165.3kJ
d) 134.2kJ
Answer: b
Clarification: E=mk²ω²/2.
6. A solid cast iron disk of mass 1000kg is rotating at 350rpm. Diameter of the disk is 1m and time taken to come to stop the disk by brake is 1.6sec.Square of radius of gyration is 0.2. Calculate the average angular velocity during braking period.
a) 15.45rad/s
b) 17.32rad/s
c) 18.32rad/s
d) None of the mentioned
Answer: c
Explanaton: ω(avg)=[ω()initial+ω(final)]/2.
7. A solid cast iron disk of mass 1000kg is rotating at 350rpm. Diameter of the disk is 1m and time taken to come to stop the disk by brake is 1.6sec.Square of radius of gyration is 0.2. Calculate the angle through which disk rotated during braking period.
a) 27.5rad
b) 24.6rad
c) 29.3rad
d) 32.4rad
Answer: c
Clarification: ω(avg)=[ω()initial+ω(final)]/2 and θ=ωt.
8. A solid cast iron disk of mass 1000kg is rotating at 350rpm. Diameter of the disk is 1m and time taken to come to stop the disk by brake is 1.6sec.Square of radius of gyration is 0.2. Calculate the torque capacity of the brake.
a) 812.4N-m
b) 4583.6N-m
c) 612.4N-m
d) Noe of the listed
Answer: b
Clarification: M=E/θ.
9. An automobile brake is only used to reduce the speed or bring the vehicle to hault.
a) Yes
b) No, it also be used to hold the car
c) Brake acts only onmoving vehicles
d) None of the mentioned
Answer: b
Clarification: It can also be used to hold the car stationary.