light and it's mass

According to Einstein , the body having some mass hold some energy but the body having no mass doesnot hold any energy but it isn't true in terms of light . To hold energy other bodies require mass but light but simply don't agree.

Light consists energy due to the momentum of it. But is it true that momentum transforms massless objects to gain some mass ? Probably not !.

Let us suppose momentum of light be 'P' then we know ,

p=mass*velocity -------(i)

Also

acceleration = velocity/time

a=v*t--------(ii)

p=m*v

p=m*a*t --- (iii)

p=d/v*a*t where mass=density*volume

Hence, mass can also be calculated as :

Mass=(density*volume*acceleration*time)/velocity

And K.E can be calculated as:

K.E=(velocity*density*volume*acceleration*time)/2