Answer:
The electric force will be 0 N
Explanation:
From the question we are told that
The magnitude of the charge is 
Generally from Coulombs law the electric force between two charges is mathematically represented as

Here r is the distance of separation between that two charges.
Now from the question we are told that the charge is far away from any other charge hence we can say that the distance between the charge and any other charge is 
So

=> 
Hence the electric force will be 0 N
I think c I’m not sure tho
Answer:
a)Work done by fireman= 2.15 Btu
b) Time t= 0.86 sec
Explanation:
Given that
Weight = 280 lbf
We know that 1 lbf = 4.44 N
so 280 lbf = 1245.5 N
Weight =1245.5 N
Height h = 60 ft
We know that
1 ft = 0.3048 m
So 60 ft = 18.28 m
h =18.28 m
Power = 3.5 hp
We know that
1 hp =0.74 KW
So 3.5 hp = 2.61 KW
Power = 2.61 KJ/s
So the work done by fireman = Weight x h
Now by putting the values
Work done by fireman= 1245.5 x 18.28 J
Work done by fireman= 2267.74 J
Work done by fireman= 2.26774 KJ
We know that 1 Btu= 1.05 KJ
So 2.266 KJ = 2.15 Btu
Work done by fireman= 2.15 Btu
We know that ,rate of work is called power.
Power x time = work
2.61 x t = 2.26
So t= 0.86 sec
By communication, competition and symbiosis. These are the three main ways organisms interact.
Halogens therefore react most vigorously with Group 1 and Group 2 metals of all main group elements.