Question

Two objects move towards each other. The speed of first object is $5m{s}^{-1}$ and the speed of the second object is $10m{s}^{-1}$. If the distance between the objects is initially $60m$, what is the time taken by the two bodies to meet?

• A. $1s$
• B. $2s$
• C. $4s$
• D. $8s$

Answer 1

The correct option is C $4s$

Given, speed of first body = $5m{s}^{-1}$.
Speed of second body = $10m{s}^{-1}$.
Let the time taken for the two bodies to meet be $t$.
Distance travelled by the first body = $5\times t$.
Distance travelled by the second body = $10\times t$.
Since the total of the distance travelled = $60m$.
Since the objects are moving opposite to each other, the equivalent speed is the sum of the individual speeds.
$\Rightarrow 5t+10t=60$
$\Rightarrow 15t=60$
$\Rightarrow t=4s$.