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show that the famous 'Einstein equation' E=mc^2 is dimentionally consistent?
6 Answers
- ?Lv 71 decade agoFavorite Answer
The fundamental units are mass, length & time:
E = F*L = m*a*L = m*(L/t²)*L = m*(L²/t²)
mc² = m*(L²/t²)
QED
- electron1Lv 71 decade ago
show that the famous 'Einstein equation' E=mc^2 is dimentionally consistent?
E = mass * c^2
E = energy
m = mass = kg
c = speed of light = 3 * 10^8 m/s
c^2 = m^2 / s^2
mc^2 = kg * m^2/s^2
The unit of energy = Joule = Newton * meters
Newton is unit of Force, F = mass * a
Mass = kg, a = m/s^2, so F = kg * m /s^2
Joule = Newton * m = kg * m /s^2 * m
Joule = kg * m^2 /s^2
mc^2 = kg * m^2/s^2
Units agree
- PearlsawmeLv 71 decade ago
Since the question is whether the equation is dimensionally correct? we need not analyse it dimensionally. It is enough, if the left and right side of this equation represents the same physical quantity.
L.H.S is energy.
R.H.S is mass times square of velocity which is kinetic energy and hence energy.There are no other quantity in the right side other than energy.
Hence it is dimensionally correct.
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- 1 decade ago
sure, same as kinetic energy = 1/2 mv^2
m is in kg
v is in m/s
so mc^2 has the same units as 1/2 mv^2 Both are in kg*m^2/s^2 which is a Joule, the standard unit of energy (E)
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- 4 years ago
The unit of energy = Joules =Nm
As,Energy =F×L
Dimensions of l.h.s of eq.= [E]= [ML^2 T^-2]
Dimensions of r.h.s of the eq. = [ML^2 T ^-2]
SINCE lhs = rhs
Eq is dimensionally consistent
- Anonymous1 decade ago
Use dimensional analysis and the base units for M, L, T.