Question

Suppose an elephant has a mass of 2750 kg.How fast, in meters per second, does the elephant need to move to have the same kinetic energy as a 66.5-kg sprinter running at 9.5 m/s?

Answer 1

Given:

The mass of the elephant is M = 2750 kg

The mass of the sprinter is m = 66.5 kg

The speed of the sprinter is v = 9.5 m/s

The kinetic energy of the sprinter is equal to the kinetic energy of the elephant.

Required: The speed of the elephant

Step-by-step explanation:

The kinetic energy of the sprinter is equal to the kinetic energy of the elephant.

The speed of the elephant can be calculated by the formula

`\begin{gathered} K.E._(elephant)=K.E._(sprinter) \\ (1)/(2)MV^2=(1)/(2)mv^2 \\ V=\sqrt{(mv^2)/(M)} \end{gathered}`

On substituting the values, the speed of the elephant will be

`\begin{gathered} V=\sqrt{(66.5*(9.5)^2)/(2750)} \\ =1.48\text{ m/s} \end{gathered}`

Thus, the speed of the elephant is 1.48 m/s

Final Answer: The speed of the elephant is 1.48 m/s