The answer is positive thoughts
Answer:
Biosphere is the part of the earth where life exists.
Answer:
a) 
Explanation:
a) Let consider that disk accelerates and decelerates at constant rate. The expression for angular acceleration and deceleration are, respectively:
Acceleration

Deceleration

Since angular acceleration and deceleration have same magnitude but opposite sign. Let is find the maximum allowed angular speed from maximum allowed centripetal acceleration:




Maximum magnitude of acceleration/deceleration is:

The least time require for rotation is:

