Question

Which has the larger kinetic energy, a 10 g bullet fired at
500 m/s or a 75 kg student running at 5.5 m/s?

Short answer

Bullet has larger kinetic energy compared to student.

Step-by-step solution

Given

Mass of bullet = 10 g bullet and velocity 500 m/s

Mass of student = 75 kg and velocity= 5.5 m/s?

Explanation

Calculate the kinetic energy using $K.E.=0.5\times m\times v^2............................\left(1\right)$

Now find the kinetic energy of bullet and students using the equation (1)

$$\begin{gathered} K{E}_{bullet}.=0.5\times m\times v^2 \\ K{E}_{bullet}=0.5\times 0.010\times {500}^2=1250\mathrm{J} \end{gathered}$$

Similarly

$$\begin{gathered} K{E}_{student}=0.5\times m\times v^2 \\ K{E}_{student}=0.5\times 75\times 5.5^2=1134.38\mathrm{J} \end{gathered}$$

We can see KE_bullet > KE_student