Question

A boat moves at 10.0 m/s relative to the water. if the boat is in a river where the current is 2.00 m/s, how long does it take the boat to make a complete round trip of 1 000 m upstream followed by a 1 000-m trip downstream?

Answer 1

208.33 s

Explanation:

We are given that

Speed of boat=10 m/s

Current speed =2 m/s

If going upstream , total speed=10+12=12 m/s

If going downstream, total speed =10-2=8 m/s

We have to find the total taken by the boat to complete round trip of 1000 m upstream followed by a 1000 m trip downstream.

Distance=1000 m

Time going upstream=
`(1000)/(8)=125 s`

Time going downstream=
`(1000)/(12)=83.33 s`

Total time=125+83.33=208.33 s

Hence, boat takes 208.33 s to make a complete round trip of 1000 m upstream followed by a 1000 m trip downstream.

Answer 2

upstream = 1000/(10-2) = 1000/8 = 125 seconds

downstream = 1000/(10+2) = 1000/12 = 83.33 seconds

125+83.33 = 208.33 seconds

208.33/60 = 3.472 minutes.

Round answer as needed