All Solutions
Page 961: Lesson Check
$$
E=mc^2.
$$
$m = 1.0$ kg
$textbf{Find:}$ rest energy, $E$
$$
textbf{Formula:}
$$
$$
begin{gather}
E = mc^2
end{gather}
$$
Using Eq (1), we can find $E$ as follows:
$$
begin{align*}
E &= 1.0 text{ kg} times c^2 \
&= 1.0 text{ kg} times (3.0 times 10^8 text{ m/s})^2 \
&= boxed{9 times 10^{16} text{ J}}
end{align*}
$$
E = 9 times 10^{16} text{ J}
$$
$$
E=1text{ kg}times(3times10^{8}text{m/s})^2=9times 10^{16}text{ J}.
$$
$m = 1.0$ kg
$v = 0.50 c$
$textbf{Find:}$ relativistic energy, $E$
$$
textbf{Formula:}
$$
$$
begin{gather}
E = dfrac{mc^2}{sqrt{1 – dfrac{v^2}{c^2}}}
end{gather}
$$
Using Eq (1), we can find $E$ as follows:
$$
begin{align*}
E &= dfrac{1.0 text{ kg} times c^2}{sqrt{1 – dfrac{(0.50c)^2}{c^2}}} \
&= boxed{1.04 times 10^{17} text{ J}}
end{align*}
$$
$$
E=frac{1text{ kg}times c^2}{sqrt{1-0.5^2}} = 1.04times 10^{17}text{ J}.
$$
$Delta E = 120$ J
a) Due to the heating of the pan, energy was absorbed, since there is an increase in energy in the system, we can say that the mass of the pan increased by virtue of the mass-energy equivalence principle: $E = mc^2$
b) The change in mass can be calculated by using the mass-energy equivalence formula as follows:
$$
begin{align*}
Delta E &= Delta m c^2 \
Delta m &= dfrac{Delta E}{c^2} \
&= dfrac{120 text{ J}}{c^2} \
&= 1.33 times 10^{-15} text{ kg}
end{align*}
$$
The change is mass of the pan is $boxed{1.33 times 10^{-15} text{ kg}}$
1.33 times 10^{-15} text{ kg}
$$
b) The increase is directly calculated using equivalence relation
$$
Delta m = frac{120text{ J}}{c^2} =1.33times 10^{-15}text{ kg}.
$$