Which of the following is experiencing a net force of zero? a. A person jumping on a trampoline.
b. A rocket launching into space.
c. A racecar driving around a circular track.
d. A pencil sitting on a desk.

The answer which is not a detail carson used to describe the pool in the cave at low tide is b.  hundreds of periwinkles browse the branches and roots of the trees. 

Two 10¢  coins  (dimes)  carrying identical charges  are  lying 2.5 m apart  on a  table.  if each  of  these coins experiences  an  electrostatic force  of  magnitude 2.0 n due  to the  other coin.  the charge on each coin is :     52.2 uc

An em wave does not require a medium, while a mechanical wave does. 

Electrical charge is measured in coulomb.(c). the amount of an electrical charge that moves in a circuit depends on the current flow and how long it flows for. a current of 10 a flows for 30 s,then 10 x=300 coulombs of electrical charge moves