Relative Motion Problems

okay, so today we didn't really learn something new. we just went over the questions on page 10 of the first booklet we were given: Acceleration & Relative Velocity

I don't know about you guys but questions 4-7 gave me a hard time solving them, until Ms. Kozoriz gave me some really important tips on how to solve them.

so here are some steps of how you can solve them.

1) draw your x-axis and y-axis

2) draw the first information that you are give on the graph

3) draw the second information that you are given, but draw it from the end tip of the first information. i will show you what i mean by this

4) now you use this equations to solve for y and x.

y = sin(angle) * given distance or velocity

x = cos (angle) * given didstance or velocity

5) now you make sure that you have the total x or y

6) use the x and y to find the resultant velocity if you are asked to find it.

7) after the above steps you now have enough information to solve for tan (angle)

okay let us put the above steps into actions

question: A dog's owner walks 20 meters due west and then turns and walks 45 degrees south of west a distance of 150. where is he with the respect to where he started?

y = sin45 (150) = -106

x = cos45 (150) = -106

the total value for x is -126

this is because we had -20m which we were given in the question, plus the -106 that we just solved for.

total value for y is -106

* okay now you might be thinking why this values are negative, and that is becuase if you look on the graph the side that they are drawn on is negative for both y and x axis

now to find the resultant distance you use pythegorean theorem.

r = 165

now the last thing is find the angle.

tan (angle) = 106/126

tan (angle) = 40s degrees south of west

so now this is what you do when you get a question like that. just solve it step by step.