# River Flow Rate: Find Answer b in 1.5m/s at 28°

• ChloeYip
Keep up the good work!In summary, the conversation discusses solving for the rate of a river's flow based on the angle and distance of swimming across it at a constant rate. The correct answer is found by using the formula v cos theta, and the incorrect options are provided as multiple choice options.
ChloeYip

## Homework Statement

You want to swim straight across a river that is 76 m wide. You find that you can do this if you swim at an angle of θ = 28° from the upstream direction at a constant rate of 1.5 m/s relative to the water. At what rate does the river flow? The angle θ is measured from the river bank (directly upstream is θ = 0° while directly across the river is θ = 90°).
(a) 1.8 m/s (b) 1.3 m/s (c) 1.6 m/s (d) 0.70 m/s (e) 2.1 m/s

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## The Attempt at a Solution

1.5 sin28° = 0.70m/s

Thanks

How did you formulate your solution attempt? Did you make a sketch? If so, can you share it?

Oh thanks...
I just discover my drawing is wrong...
The answer is by v cos theta

ChloeYip said:
Oh thanks...
I just discover my drawing is wrong...
The answer is by v cos theta
Okay! It's great that you worked it out yourself!

## 1. What is the formula for calculating river flow rate?

The formula for calculating river flow rate is Q = A x v, where Q is the flow rate, A is the cross-sectional area of the river, and v is the velocity of the river.

## 2. How do you determine the cross-sectional area of a river?

The cross-sectional area of a river can be determined by measuring the width and depth of the river at a specific point and multiplying them together.

## 3. How is river flow rate measured?

River flow rate can be measured using a current meter, which is a device that measures the velocity of the water at a specific point in the river.

## 4. What units are used to measure river flow rate?

River flow rate is typically measured in cubic meters per second (m3/s) or cubic feet per second (ft3/s).

## 5. How does temperature affect river flow rate?

Temperature can affect river flow rate by influencing the density of the water. As water temperature increases, its density decreases, resulting in a decrease in flow rate. Conversely, colder water will have a higher density and flow rate.

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