The electrostatic force between two charges Q1 and q is given by

where
ke is the Coulomb's constant
Q1 is the first charge
q is the second charge
r is the distance between the two charges
Re-arranging the formula, we have

and since we know the value of the force F, of the charge Q1 and the distance r between the two charges, we can calculate the value of q:

And since the force is attractive, the two charges must have opposite sign, so the charge q must have negative sign.
Answer:
D
Explanation:
We must never use a piece of pipe as a leverage extension on the handle on a wrench.
Hence option d is correct.
Answer:
As investigated by Sir Isaac Newton,the white light contains all colours of light.
This shorten by a term rainbow colours.
<h2><em>ight hull up...................................</em></h2>