Question

A boat can be rowed at →vbw = 8.5 km/h in still water. In the question below, think about motion from the point of view of an observer on the boat and the point of view of an observer on the shore. (a) How much time is required to row 1.2 km downstream (East) in a river moving at =3.3 km/h relative to the shore?

a) 0.12 hours
b) 0.15 hours
c) 0.18 hours
d) 0.20 hours

Answer 1

The boat's total effective speed when moving downstream is 11.8 km/h, and the time required to row 1.2 km downstream is approximately 0.10 hours. However, the options provided in the question do not match this answer, indicating a possible error in the question or answer choices.

Step-by-step explanation:

The question concerns calculating the time required for a boat to travel downstream in a river when the speed of the river's current and the speed of the boat in still water are known. Given that the boat moves at 8.5 km/h in still water and the river's current is 3.3 km/h relative to the shore, the total effective speed of the boat moving downstream is the sum of these two speeds, which is 8.5 km/h + 3.3 km/h = 11.8 km/h.

To find out how long it takes to cover 1.2 km downstream, we use the formula:
Time = Distance ∕ Speed
Therefore, the time to cover 1.2 km downstream is 1.2 km ∕ 11.8 km/h, which equals approximately 0.10 hours. Looking at the available options, there doesn't seem to be a correct match, so it's likely that there's a mistake in the options provided or the question might need to be revisited.