Answer:

Explanation:
We are given that
Diameter,d=

Radius,r=
Density,
Total number of electrons,n=39
Charge on electron =
Total charge=
Distance,s=2mm=
Mass =
Initial velocity,u=0
Final speed,v=4.5 m/s




Force,F=ma





Well it does carry blood and oxygen! Sorry but I'm not sure about 2 and 4.
1) 0N... friction opposes the motion of an object, since the block is at rest there is no motion thus no friction
2) F=ma
= (5.5kg)(30m/s)
=165 N
B. they both involve wave interaction.