This is a physical change because there isn’t a change in composition of the substance, sand. It is only changing the shape, not having a chemical reaction of any sort.
I hope this helps!
The answer to your question is kidneys
Answer:
a) V1=11.05m/s V2=92.07m/s V3=17.24m/s
b) KE = 16238.26J
Explanation:
For tangential speeds:



For the kinetic energy, it can be calculated as:

Where:



So,

KE=16238.26J
When you rub the balloons, it will take electrons away, which is negative. So, the balloons are negative