Question

a penny has mass of about 3g.compute the energy that would be released if it's rest mass were entirely converted into the energy (2.7×10^14J)

Answer 1

Since we know that the mass-energy equivalence is $1\, kg \leftrightarrow 8.988\times 10^{16}\, J$, we find:

$E=m_0c^2=(3\,\cancel{g}(\frac{1\,\cancel{kg}}{1000\,\cancel{g}})(\frac{8.988\times10^{16}\, J}{1\,\cancel{kg}})) \\\implies E=2.6964\times 10^{14}\,J$

In conclusion, the energy that would be released (if its rest mass

were entirely converted into energy) is E ≊ 2.7 X 10¹⁴ J.

Reference:

• Young, H. D., & Freedman, R. A. (2015). University Physics with Modern Physics and Mastering Physics. Academic Imports Sweden AB.