Air resistance is the answer
Blood
I learned this in anatomy, and I've taken it twice
To solve this problem we will apply the concepts related to the balance of Forces, the centripetal Force and Newton's second law.
I will also attach a free body diagram that allows a better understanding of the problem.
For there to be a balance between weight and normal strength, these two must be equivalent to the centripetal Force, therefore


Here,
m = Net mass
= Angular velocity
r = Radius
W = Weight
N = Normal Force

The net mass is equivalent to

Then,

Replacing we have then,

Solving to find the angular velocity we have,

Therefore the angular velocity is 0.309rad/s
Answer:
27 Joules.
Explanation:
use the formula for kinetic energy:
KE = 1/2mv^2