Q. A stone is dropped from the top of a tall tower. The ratio of the kinetic energy of the stone at the end of three seconds to the increase in the kinetic energy of the stone during the next three seconds is
A) 1 : 1
B) 1 : 2
C) 1 : 3
D) 1 : 9
Explanation
(c) $E = \frac{1}{2}mg^{2}t^{2}$
$\frac{E_{1}}{E_{2}} = \frac{\frac{1}{2}mg^{2} \times 3^{2}}{\frac{1}{2}mg^{2}(6^{2} - 3^{2})} = \frac{9}{9 \times 3} = \frac{1}{3}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.