Answer:
225 rpm
Explanation:
The angular acceleration of the fan is given by:

where
is the final angular speed
is the initial angular speed
is the time interval
For the fan in this problem,

Substituting,

Now we can find the angular speed of the fan at the end of the 5th second, so after t = 5 s. It is given by:

where

Substituting,

Explanation:
Mass of bumper cars, 
Initial speed of car A, 
Initial speed of car Z, 
Final speed of car A after the collision, 
We need to find the velocity of car Z after the collision. Let it is equal to
. Using the conservation of momentum as :




So, the velocity of car Z after the collision is (-12 m/s). Hence, this is the required solution.
Answer:
I think the answer is b but i cannot confirm cuz this is a challenging question