Q. A ball kicked vertically up attains a height of 19.6m and returns to the point of throw. If the ball is in air for four second, then the value of acceleration due to gravity is
A) 4.9 $ms^{- 2}$
B) 9.8$ms^{- 2}$
C) 10 $ms^{- 2}$
D) $2 \times 9.8ms^{- 2}$.
Explanation
(b) $2 = \sqrt{\frac{2 \times 19.6}{g}}$ or $g = \frac{2 \times 19.6}{4} = 9.8ms^{- 2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.