# 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

Question : 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) $4.9ms^{-2}$

(B) $9.8ms^{-2}$

(C) $10ms^{-2}$

(D) $2 × 4.9ms^{-2}$