Two cars A and B are moving in same direction with velocities 30 … - Vidyadip

MCQ

Two cars $A$ and $B$ are moving in same direction with velocities $30 \,m / s$ and $20 \,m / s$. When car $A$ is at a distance $d$ behind the car $B$, the driver of the car $A$ applies brakes producing uniform retardation of $2 \,m / s ^2$. There will be no collision when ......... $m$

A
$d < 2.5$
B
$d > 125$
✓
$d > 25$
D
$d < 125$

✓

Answer

Correct option: C.

$d > 25$

c
(c)

$v^2=u^2+2 a d$

$\Rightarrow 0=(10)^2-2 \times 2 \times d_{ rel }$

$\Rightarrow \frac{100}{4} \leq d_{ rel }$

$\Rightarrow d_{ rel } \geq 25 \,m$

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