Question

A ball is thrown vertically up. If the ball reached at maximum height in $3s$. Assume air resistance is negligible. The initial velocity of the ball is most nearly :

• A. $10m/s$
• B. $15m/s$
• C. $30m/s$
• D. $45m/s$
• E. $60m/s$

Answer 1

The correct option is C $30m/s$

Given,

Time taken to reach the maximum height $t=3$ s $a=-g=-10m/s^2$

Let the initial velocity of the ball be $u$.

Final velocity of the ball at the maximum height $v=0$ m/s

Using $v=u+at$

$\therefore$ $0=u-10\times 3$ $⟹u=30$ m/s