The intensity of normal pressure between the friction lining and the brake drum at any point is proportional to square of the vertical distance from the pivot.
Explanation: It is proportional to the vertical distance linearly.
The coefficient of friction in internally expanding brakes is constant.
Explanation: Coefficient of friction is constant in these types of brakes.
The centrifugal force acting on the shoe can never be omitted.
Explanation: Centrifugal force on the internal expanding brakes is generally neglected as it is very small.
These kinds of brakes require little maintenance.
Explanation: Very little maintenance is required as there is less wear.
In internally expanding brake, a large actuating force produces a small braking torque and hence this brake isn’t used generally.
Explanation: Small actuating force produce large braking torque.
Heat dissipating capacity of internally expanding brakes is a problem.
Explanation: It has relatively poor dissipation of heat.
Internally expanding brakes never suffer the problem of self-locking.
Explanation: Due to improper design, wear may be caused which might lead to self-locking of brakes.
Moment of normal force and frictional forces about the pivot axis are 640000N-mm and 250000N-mm respectively. If force acts at a distance of 190mm from the pivoted point, calculate the actuating force.
Preloading is recommended for bearings.
Explanation: Preloading removes the internal clearances.
Needles bearings have not much load capacity as they are quite small.
Explanation: Needle bearings have quite large loading capacity as compared to their size.