Answer:
Why are they used:
A carbon brush is a sliding contact used to transmit electrical current from a static to a rotating part in a motor or generator, and, as regards DC machines, ensuring a spark-free commutation.
Answer:
in first case the torque is maximum.
Explanation:
Torque is defined as the product of force and the perpendicular distance.
τ = F x d x Sinθ
In case A: the angle between force vector and the distance vector is 90 so torque is
τ = F x d
In case B: the angle between force vector and the distance is 30°.
τ = F x d x Sin30
τ = 0.5 Fd
So the torque is maximum in first case.
If 1 ken is 1.97 meter, then 1 square ken is 3.8809 square meters, and one cubic ken is 7.645373. As for the cylindrical tank, the volume of it would be 10.835 times the radius of the cylinder time 1.97^2 times pi. As you didn't specify the radius, I can't give the exact answer but that would be how to get it.
Answer:
A. 
B. 
C. 
Explanation:
Given:
- spring constant,

- mass attached,

A)
for a spring-mass system the frequency is given as:



B)
frequency is given as:



C)
Time period of a simple harmonic motion is given as:


That only the best traits would go through. The weaker trait in the animals would eventually die off.