One of the most striking notions of Einstein's Theory of Relativity is his
time dilation concept. If a person \(P_{1}\) moves with velocity \(v\) with
respect to an observer \(P_{2}\) then a watch carried by \(P_{1}\) appears to be
running more slowly to \(P_{2}\) than to \(P_{1}\) by a (dilation) factor of
$$
\frac{1}{\sqrt{1-v^{2} / c^{2}}}
$$
Here \(c\) is the velocity of light, approximately 186,000 miles per second.
a. If \(v=c / 2\), what is the dilation factor?
b. If \(v=c / 3600\), which is 186,000 miles per hour, estimate the dilation
factor. (Hint: Consider the function \(f(x)=1 / \sqrt{1-x}\) near 0.)