A boat is able to move through still water at 20 m/s. It makes a round trip to a town 3.0 km upstream. If the river flows at 5m/s ,the time required for this round trip is:
a) 120s
b) 150s
c) 200s
d) 300s
e) 320s
Answers
V = d/t
so t = d/V
On the upstream part the boat is only going 20 m/s - 5 m/s = 15 m/s because the river pushing back.
t = 3000 m / 15 m/s = 200 s
And on the strip back the speed is 20 m/s + 5 m/s = 25 m/s because the river is now pushing you from behind adding to the speed
t = 3000 n / 25 m/s = 120 s
total time = 200 s + 120 s = 320 sec
Answer:
The time required for this round trip is e) 320s.
Explanation:
Given,
A boat can drive through still water at 20 m/s.
To find,
The time required for this round trip is.
Step 1
Velocity of boat in still water , v = 20 m/s.
The velocity of the river,
V = 5 m/s.
In the provided question boat create a round trip to a town 3 km upstream.
Thus, Total time = time taken upstream + time taken upstream.
We know, ( here all have their usual meaning ).
Total time,
( upstream velocity .
downstream velocity
Hence, The correct option is e) 320s.
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