Velocity =displacement
Change in time
D=72km/hr
Time=20s
But the S.I unit of velocity is m/s so you woul have to change 72km/hr to m/s
Changing 72km to m
1 kilometer=1000meters
Then, 72 kilometers =?
72•1000/1
=72000m
Changing 72hours to seconds
If 1 hour = 3600 seconds
Then 72 hours=?
72•3600/1
=259200 seconds
Velocity =displacement
Change in time
V= 72,000
259,2005
=0.028m/s
Answer:
The distance is 1.69 m.
Explanation:
Given that,
First charge 
Second charge 
Distance = 3.25 m
We need to calculate the distance
Using formula of electric field





Put the value into the formula





Hence, The distance is 1.69 m.
The answer is having fewer neutrons than protons or electrons.