- #1

hg10tr

- 5

- 0

## Homework Statement

Sandra needs to deliver 20 cases of celery to the farmer's market directly east across the river, which is 32 km wide. Her boat can move 2.5 km/h in still water. The river has a current of 1.2 km/h flowing downstream, which happens to be moving in a southerly direction.

a) where will Sandra end up if she aims her boat directly across the river?

b) how far will she have to walk to reach the farmer's market?

c) show how sandra could end up at her destination without walking. Include a diagram and calculations.

d) which route will result in the shortest time for sandra to reach her destination? sandra can walk 0.72 m/s when she is pulling her wagon loaded with 20 cases of celery.

## Homework Equations

velocity = displacement/time

SOHCAHTOA

## The Attempt at a Solution

I got the answer to a). I found the time taken to cross in still water (0.0128 h) and multiplied that by the current (2.5 km/h) and got 15.36 m.

For b, c and d I'm confused.

For b, I made a diagram of the journey and it created a triangle with 32 m for the horizontal side and 15.36m for the vertical side. I'm not sure if I'm supposed to use Pythagorean Theory to get the hypotenuse and that will be the distance she needs to walk to reach the market. Or use 0.0128 h and multiply that with a value?

c) I have a feeling she would have to aim upwards to end up at her destination. I know I need to use SOHCAHTOA for this question. If I used the Pythagorean theory like in b) to get the hypotenuse then I could use SOHCAHTOA to find out an angle of the triangle. I'm not sure if the question wants a distance value or angle value.

d) And for this question I am completely lost.

Any help with these questions would be greatly appreciated.