A person sitting in the ground floor of a building notices through the window, of height 1 . 5m, a ball dropped from the roof of the building crosses the window in 0 . 1s . What is the velocity of the ball when it is at

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Quantrex Academy · Accepted Answer

Correct answer: B. 14 . 5m s ^ - 1

First, recall the second equation of motion of kinematics, in terms of initial speed, time, and uniform acceleration, $s = ut + \dfrac{1}{2}a{t}^{2}$ . Now make a diagram related to motion of the particle,

A person sitting in the ground floor of a building notices through the window, of height 1 . 5m, a ball dropped from

then put the values in second equation of motion,

$⇒ 1 . 5 = u ( 0 . 1 ) + \dfrac{1}{2} ( 10 ) ( 0 . 1 ) ( 0 . 1 )$ $⇒ 15 = u + 0 . 5$

$⇒ u = 14 . 5m{s}^{- 1}$ .

A person sitting in the ground floor of a building notices through...

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