Question

18. An object is released at one bank into a river
flowing with speed 5 km/h towards east. Air is
blowing with speed 5 km/h towards north. If width
of river is 200 m, then minimum time taken by
floating object to reach the other bank is (consider
ideal situation)
(1) 144 minute (2) 3.4 second
(3) 144 second (4) 14.4 second​

Answer 1

Answer:

The minimum time by floating object to reach the other bank is 144 sec.

(3) is correct option.

Explanation:

Given that,

Distance = 200 m

Speed = 5 km/h

For minimum time, the object will move into the north direction.

We need to calculate the time

Using formula of time

$v=\dfrac{d}{t}$

$t=\dfrac{d}{v}$

Where, v = speed

d = distance

Put the value into the formula

$t=\dfrac{0.200}{5}$

$t=0.04\ hr$

Time in second

$t=0.04\times3600$

$t= 144\ s$

Hence, The minimum time by floating object to reach the other bank is 144 sec.