Question

a machine gun bullet of mass m leaves a barrel at a speed of 250ms^-1 and has a kinetic energy of 37500J. what is the mass of the bullets​

Answer 1

$\underline{\underline{\Large{\bf Given:-}}}$

$\ast\sf Speed \:of\:bullet=v=250m/s$

$\ast\sf Kinetic\:energy=E_K=37500J$

$\underline{\underline{\Large{\bf To\:find:-}}}$

$\ast\sf Mass\:of\:bullet=m$

$\underline{\underline{\Large{\bf Solution:-}}}$

$\sf We\:know\:that$

$\boxed{\sf E_k=\dfrac{1}{2}mv^2}$

$\\ \sf\longmapsto 37500=\dfrac{1}{2}\times m\times 250^2$

$\\ \sf\longmapsto 37500=125^2m$

$\\ \sf\longmapsto 37500=15625m$

$\\ \sf\longmapsto m=\dfrac{37500}{15625}$

$\\ \sf\longmapsto m=2.4g$

$\\ \underline{\underline{\sf \therefore Mass\:of\:bullet\:is\:2.4g.}}$