Answer:
1.5min
Explanation:
To solve the problem it is necessary to take into account the concepts related to Period and Centripetal Acceleration.
By definition centripetal acceleration is given by

Where,
V = Tangencial velocity
r = radius
With our values we know that


Therefore solving to find V, we have:



For definition we know that the Time to complete are revolution is given by




Reduce friction because friction just makes things harder
Answer:
Explanation:
Given
mass of sphere 
diameter of sphere 
radius 

friction will provide resisting torque so
where 







(b)time taken to decrease its rotational speed by 



(a) The work done by the bird to raise the snake on the branch is equal to the product between the weight of the snake and the height of the branch above the ground:

where
is the mass of the snake and
is the height of the branch with respect to the ground. Substituting numbers into the equation, we find

(b) The work the bird did to raise its own centre of mass from the ground to the branch is equal to the product between the bird's weight and the height of the branch:

where
is the mass of the bird. Substituting numbers into the equation, we find
