Question

A wicketkeeping glove is dropped from a height of $40\text{m}$ and simultaneously a ball is thrown upwards from the ground with a speed of $40\text{m/s}$. When will they meet?

$(g=10{\text{m/s}}^2)$

• A. $1\text{s}$ after glove is dropped
• B. $2\text{s}$ after glove is dropped
• C. $3\text{s}$ after glove is dropped
• D. $4\text{s}$ after glove is dropped

Answer 1

The correct option is A $1\text{s}$ after glove is dropped

We will use the concept of relative motion.

Suppose they meet after time $t$.

$u_{\text{rel}}=40-0=40\text{m/s}$

$g_{\text{rel}}=-10-(-10)=0$

$s_{\text{rel}}=40-0=40\text{m}$

Now,

$s_{\text{rel}}=u_{\text{rel}}t+\frac{1}{2}{g}_{\text{rel}}{t}^2$

$\Rightarrow 40=40t+0$

$\Rightarrow t=1\text{s}$