Before getting an answer for it first we have to understand nuclear fusion.
Nuclear fusion is a thermo-nuclear reaction in which two light unstable nuclei will form a heavy stable nuclei. In this process there will be some mass defect which will be converted into energy as per Einstein's mass energy equivalence theorem.
The theorem is stated as
where c is the velocity of light and m is the mass converted into energy.
One take an example of fusion in sun where 4 hydrogen atoms combine to form a helium nucleus which are explained below-



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Here
is the positron.
In this process very high temperature is needed which is approximately equal to the temperature of the sun i.e 
Such temperature is very difficult to initiate the reaction on the earth surface. It should be carried out in an sustainable way also .Otherwise It will cause nuclear hazards.
Answer:

Explanation:
you mean deceleration right ? because the acceleration is 250m/s
<span>Volume of air in the balloon 1.01 x 10^6 L
Density of air is 1.20 g/l
Mass = Density X Volume
So mass of the air in the Balloon= ( 1.01 x 10^6) X 1.20 = 1.212 x 10^6 g
As the air is heated, the volume of air in the balloon expands to 1.10x 10^6 L
Density= Mass/ voume
So the Density of heated air = 1.212 x 10^6/ 1.10x 10^6 = 1.101 g/l
The answer is 1.101 g/l.</span>
Answer:
The velocity of the man from the frame of reference of a stationary observer is, V₂ = 5 m/s
Explanation:
Given,
Your velocity, V₁ = 2 m/
The velocity of the person, V₂ =?
The velocity of the person relative to you, V₂₁ = 3 m/s
According to the relative velocity of two
V₂₁ = V₂ -V₁
∴ V₂ = V₂₁ + V₁
On substitution
V₂ = 3 + 2
= 5 m/s
Hence, the velocity of the man from the frame of reference of a stationary observe is, V₂ = 5 m/s