Answer:


Explanation:

Required
The units of A and B
From the question, we understand that:

This implies that each of
and
will have the same unit as 
So, we have:


The unit of t is (s); So, the expression becomes

Divide both sides by 


Answer:

Explanation:
We are given that
Gravitational force=
r=0,U(0)=0
We know that
Gravitational potential energy=


Substitute r=0 ,U(0)=0


Substitute the value

<span>Nitrogen is used to protect steel from water because nitrogen has stable physical properties that enables the nitrogen to be resistant to water molecules. Nitrogen also serves as a coat for the steel to not be corroded easily</span>
The right answer is c because it absorbs the heat then it pushes it away like radiation