Answer
(a) $KE = 2.184\times 10^{-18}~J$
(b) KE = 9.80 J
(c) The speed would be $v = 2.58~m/s$, which seems perfectly reasonable for a young person.
Work Step by Step
(a) $KE = \frac{1}{2}mv^2$
$KE = \frac{1}{2}(9.109\times 10^{-31}~kg)(2.190\times 10^6~m/s)^2$
$KE = 2.184\times 10^{-18}~J$
(b) We can find the speed $v$ after the object falls 1.0 meter.
$v^2 = v_0^2+2ay = 0+2ay$
$v = \sqrt{2ay} = \sqrt{(2)(9.80~m/s^2)(1.0~m)}$
$v = \sqrt{19.6}~m/s$
$KE = \frac{1}{2}mv^2$
$KE = \frac{1}{2}(1.0~kg)(\sqrt{19.6}~m/s)^2$
$KE = 9.80~J$
(c) $KE = \frac{1}{2}mv^2$
$v^2 = \frac{2\times 100~J}{30~kg}$
$v = \sqrt{\frac{200~J}{30~kg}}$
$v = 2.58~m/s$
The time to run 100 meters would be $\frac{100~m}{2.58~m/s}$, which is 38.8 seconds, and this seems perfectly reasonable for a young person.
