Stuck on vector addition and subtraction

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SUMMARY

The forum discussion focuses on solving vector addition and subtraction problems in physics. The first problem involves determining the angle a boat should point to move straight across a river, given its speed and the river's current. The second problem requires calculating a plane's ground velocity while accounting for a crosswind. Participants emphasize the importance of using the Pythagorean theorem for displacement and suggest showing work for better assistance.

PREREQUISITES
  • Understanding of vector components and their representation
  • Knowledge of the Pythagorean theorem
  • Familiarity with basic trigonometry, particularly sine and cosine functions
  • Concept of relative velocity in physics
NEXT STEPS
  • Study vector resolution techniques in physics
  • Learn how to apply the law of sines and cosines for vector problems
  • Explore examples of relative velocity in different contexts
  • Practice solving real-world problems involving wind and water currents
USEFUL FOR

This discussion is beneficial for students studying physics, educators teaching vector concepts, and anyone interested in applying vector analysis to real-world scenarios such as navigation and aviation.

victorhugo
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Hello, here is a couple of example problems I'm not sure how to do, if someone could please explain how to do it I would greatly appreciate it!

Subtraction:
"A river flows at 0.8 m/s. If a boat moves across the water at 2m/s at what angle should it point so that it moves straight across the river perpendicular to the bank?"

Addition:
"A plane flies at a bearing of 270 degrees at 200km/h through a cross wind blowing from a bearing of 360 degrees at 80km/h. What is the plane's velocity over the ground?"

Thank you!
 
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You have to at least make an attempt to answer the questions.
 
I actually don't know what to do... the only way I learned is to get the displacement by using Pythagoras theorem, then diving that by the time to get the average velocity, so that's why I'm asking if someone could tell me what to do here :/
 
Take one of your problems, and use the procedure you know on it. Show your work. Then people here can help you.
 

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