Question

A body is projected vertically upwards with certain velocity. The magnitude of its displacement in the last second of its upward motion is.............

• A. $2g$
• B. $\frac{g}{3}$
• C. $\frac{g}{2}$
• D. $\frac{3g}{2}$

Answer 1

The correct option is C $\frac{g}{2}$

Time taken by the ball to reach the maximum height is
$v=u-gt$
$t=\frac{u}{g}$
Distance travelled in n th second is
$s=u+\frac{a}{2}(2n-1)$
$s=u-\frac{g}{2}(2\frac{u}{g}-1)$
Therefore, the magnitude of the displacement in the last second of its upward motion $=\frac{g}{2}$