Answer:
a. the force between them quadruples
Explanation:
The electrostatic force between two charges is given by

where
k is the Coulomb's constant
q1 and q2 are the two charges
r is the separation between the two charges
In this problem, the charges on both objects are doubled, so

While the distance does not change, so the new force will be

so, the force will quadruple.
Answer:
200 m / min
Explanation:
Total distance = 2000 m
Total time = 2+4+1+3 = 10 minutes
Average speed = 2000 m / 10 min = 200 m/min
My answer is "Watt per square meter".
Answer:
4 hertz
Explanation:
The defination of freqyency = the total no of cycle made by a wave in one second .
so,
cycle or vibrations=60
tame taken = 15
now,
frequency = no. of cycle / time taken
= 60/15
=4 hertz
hence, the its frequency = 4hertz