Question

Speed 48km/hr cross in 21 sec find length of train

Answer 1

$48\ km/h=\frac{48000}{3600}\ m/s=\frac{40}3\ m/s\\\\\textrm{Length of train is:}\\l=vt=\frac{40}3\cdot21\ m=40\cdot7\ m=280\ m$