Question

When a ball is thrown up vertically with velocity $V_0,$ it reaches a maximum height of '$h$'. If one wishes to triple the maximum height then the ball should be thrown with velocity. (AIIMS 2005)

• A. $\sqrt{3}{V}_0$
• B. $3V_0$
• C. $9V_0$
• D. $3/2V_0$

Answer 1

The correct option is A $\sqrt{3}{V}_0$

When the ball reaches maximum height, velocity, v = 0
$\Rightarrow u^2-2gh=v^2=0$
$\Rightarrow h\propto u^2$
$\Rightarrow \frac{h_1}{h_2}=(\frac{u_1}{u_2}{)}^2$

According to question height has to be tripled.
$\Rightarrow 3=(\frac{u_1}{v}{)}^2$
$\Rightarrow u_1=\sqrt{3}V.$