Question

Suppose an elephant has a mass of 2800 kg. show answer No Attempt How fast, in meters per second, does the elephant need to move to have the same kinetic energy as a 77-kg sprinter running at 8.5 m/s

Answer 1

Answer:

The speed of elephant must be 1.4 m/s.

Explanation:

Mass of the elephant, M = 2800 kg

Mass of sprinter, m = 77 kg

Speed of sprinter, v = 8.5 m/s

It is required to find the speed of elephant to have the same kinetic energy as that of sprinter. So,

$K_e=K_s\\\\\dfrac{1}{2}MV^2=\dfrac{1}{2}mv^2\\\\MV^2=mv^2\\\\V=\sqrt{\dfrac{mv^2}{M}} \\\\V=\sqrt{\dfrac{77\times 8.5^2}{2800}} \\\\V=1.40\ m/s$

So, the speed of elephant must be 1.4 m/s.