Question

If a body of mass 20 gm falls from a height 200 m and its total potential energy is converted into kinetic energy, at the point of contact of the body with earth surface, then what is the decrease in potential energy of the body? ($g=10m/s^2$)

• A. 20 J
• B. 40 J
• C. 60 J
• D. 90 J

Answer 1

The correct option is B 40 J

Change in PE: $mgh=20\times {10}^{-3}\times 200\times 10=40J$