A stone is dropped from the top of a tower of height h=125m. After 1 second another stone is dropped from the balcony 'x' m below the top of the tower
If both reach the ground simultaneously then the value of 'x' is (g = 10ms 2)
(A) 80 m
(B) 45 m
(C) 120 m
(D) 5 m
Answers
Answer:
45 m
Explanation:
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Answer:
(B) x = 45 m
Explanation:
Height of tower = 125 m (s₁)
Let Stone 1 = St₁ and Stone 2 = St₂
Initial velocity of St₁ = 0 m/s
Acceleration due to gravity = 10 m/s²
Initial velocity of St₂ = 0 m/s
Distance which St₂ has to cover = 125-x (s₂)
By 2nd equation of motion,
s₁ = u t + 1/2 at²
125 = (0) (t) + 1/2 × 10 × t²
125 = 5t²
25 = t²
5 s = t
∴ Stone 1 takes 5 seconds to cover 125 m. Now, if Stone 2 has to reach simultaneously with Stone 1, then it must travel the required distance (125-x) in 5-1 = 4 seconds.
s₂ = u t + 1/2 at²
125-x = (0) (4) + 1/2 × 10 × 4²
125-x = 5 × 16
-x = 80-125
x = 45 m (ANS.)
THEREFORE, THE SECOND STONE WAS RELEASED FROM A HEIGHT OF 45 M BELOW THE HIGHEST POINT OF THE TOWER.