An objecte of mass 5 kg falls from rest through a vertical distance of 20 m and reaches velocity 10 m/s. How much work is done by push of air on the object $(g=10 m/s^2)$

Question

\[(a)\;120\;J\quad (b)\;-750\;J \quad (c)\; -450\;J \quad (d)\;250\; J\]