Question

A body is thrown upwards with velocity 100 ${ms}^{-1}$ and it travels 5 m in the last second of its upward journey. If the same body is thrown upwards with velocity 200 ${ms}^{-1}$, the distance it will travel in the last second of upward journey is

• A. 5 m
• B. 10 m
• C. 20 m
• D. 25 m

Answer 1

The correct option is A 5 m

For case $2$ there is no effect of case $1$.

Now

$V^2=u^2-2gS$

$0={200}^2-2^{\star }{10}^{\star }S$

$40000/20=S$

$S=2000$ metres

$V=u+g^{\star }t$

$0=200-{10}^{\star }t$

$t=20$sec

In last second distance,

$S_{20}=u+\left(1/2\right)g^{\star }(2t-1)$

$=200-(1/2{)}^{\star }{10}^{\star }39$

$=200-195$

$=5$ metres.