Question

How fast would a(n) 85 kg man need to run in order to have the same kinetic energy as an 8.0 g bullet fired at 410 m/s?

Answer 1

Answer:

V = 3.97 m/s

Explanation:

Mass of a man, M = 85 kg

Mass of a bullet, m = 8 g = 0.008 kg

Speed of bullet, v = 410 m/s

We need to find the speed of a man in order to have the same kinetic energy as that of the bullet. Let the kinetic energy of the bullet is k. So,

$k=\dfrac{1}{2}mv^2\\\\k=\dfrac{1}{2}\times 0.008\times 410^2\\\\k=672.4\ J$

Since, k = K (K is the kinetic energy of the man and Let V is the speed)

$K=\dfrac{1}{2}MV^2\\\\V=\sqrt{\dfrac{2K}{M}} \\\\V=\sqrt{\dfrac{2\times 672.4}{85}} \\\\V=3.97\ m/s$

So, the speed of the man is 3.97 m/s.