Physics Help Thread

Seeing as this is my 3rd year of taking Physics in college I thought I would help anyone else out who is just beginning or is stuck on a rather difficult problem.

This means that I will help you get to the answer. I won't work out the entire problem for you and just give it to you since you don't want to put any work into it. I have no problem showing you how to get to the end but you need to put forth the effort. Me just doing your homework is only going to make the class harder for you. Trust me on this one.

I will try and check this everyday at about 2:00pm PST. You can also IM me at YZFRydn

We pretty much decided that these kind of threads are pretty redundant to the whole point of the section. People are supposed to make a thread for each question they have. Try to answer questions that people post in threads. Thanks!

Dang, Shmads beat me to it. I guess that is why he is a mod.




for now.....

This is true. I guess either way it will still be cluttered. Sorry.

hi this is my first year in physics and i understand everything when i have notes.. but im having a hard time with this one problem could you help me out???


what is the magnitude and direction of her net displacement?


-- i know u have to use the pythagorean theorem, but do u use the 2 net displacements that i have ( net x and net y )??

-- my net x is 8 and my net y is -15

Tell me the whole question.

The net values are they vectors or scalars? I need more information unless I just kind of guess what the question is asking.

ok..
a girl scout has to sell cookies in her neighborhood. after walking out her door, she initially walks 15 meters, East, at 1m/sec. to arrivie at the first house. it takes her 180 seconds to ring the doorbell. she then walks 17meters North, at 1m/sec to arrive at the next house, once more she takes another 180 seconds to explain the sale. next she walks 25 meters, West at 0.5m/sec with 180 seconds explaing. to reach her 4th house she walks 16meters East at 0.5 with 180 seconds to complete her sale. realizing she is out of time she jogs 18meters East at 1.5m/sec to her 5th customers house completes her sale in 180 seconds, and runs 16meters, South at 2m/sec to her 6th and final house where after 180 seconds she barely makes her deadline.



total distance = 107m/sec
total time=134sec (from her home to house 6)
total time required to give sales and collect orders= 1808*6+134=1214
average speed=.88m/sec
net x =8
net y=-15

we also had to draw all the vectors on graph paper!

Okay, now, take every single vector pair and arrange it in a column. Put the magnitude on the left, and the degree (theta) on the right. Once you have done that, make another two columns, one labeled X. The other labeled Y.

Once you have your table set up, take the magnitude and multiply it by cos(theta) to get X, and then multiply it by sin(theta) to get Y. Once you have all that done post.

travel times x y
15sec 15 0
17sec 0 17
50sec -25 0
32sec 0 -16
12sec 18 0
8sec 0 -16




all i need to know is how to find the magnitude and direction of her net displacement.
my measurements on my graph are 3.8cm, 6.5cm and 7.5 cm where i drew the final scaled vector from the 6th house and back to where she stared from.

Which is what I am trying to tell you how to do. AIM-YZFRydn