A train starts from station $A$ with uniform acceleration $a_{1}$ for some distance and then goes with uniform retardation $a_{2}$ for some more distance to come to rest at station $B .$ The distance between stations $A$ and $B$ is $4 k m$ and the train takes $\frac{1}{15} h$ to complete this journey $.$ If accelerations are in $k m$ per square minute $,$ then the value of $\frac{1}{a_{1}} + \frac{1}{a_{2}}$ in suitable unit is $_______.$

see full answer

Talk to JEE/NEET 2025 Toppers - Learn What Actually Works!

Real Strategies. Real People. Real Success Stories - Just 1 call away

An Intiative by Sri Chaitanya

$6$

$2$

$9$

$4$

answer is B.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

Using velocity - time graph of the train

$t_{1} + t_{2} = \frac{1}{15} h = 4 m i n$

$v = a_{1} t_{1} = a_{2} t_{2}$

$s = \frac{1}{2} (t_{1} + t_{2}) v \Rightarrow 4 = 2 v$

$t_{1} + t_{2} = v [\frac{1}{a_{1}} + \frac{1}{a_{2}}] \Rightarrow 4 = 2 [\frac{1}{a_{1}} + \frac{1}{a_{2}}]$

$\Rightarrow \frac{1}{a_{1}} + \frac{1}{a_{2}} = 2$

Watch 3-min video & get full concept clarity

JEE

NEET

Foundation JEE

Foundation NEET

CBSE