• Support PF! Buy your school textbooks, materials and every day products Here!

A Coordinates and Interval Question

  • Thread starter jenn047
  • Start date
  • #1
5
0

Homework Statement


During a 4.95 s interval, a particle's coordinates change from x = 10.4 m, y = 4.95 m to x = 31.5 m, y = -4.95 m. Assuming the particle's velocity is constant, what will its coordinates be at the end of the next 4.95 s interval?

x= ____m
y= ____m

Homework Equations





The Attempt at a Solution


My first thought was to take the x and y's given and find y=mx+b however I'm not sure that it is relevant or even helpful.

Thanks.
 

Answers and Replies

  • #2
CompuChip
Science Advisor
Homework Helper
4,302
47
You should consider both directions independently.

So x and y satisfy
x = u t + a,
y = v t + b

Equivalently, the distance covered in the second 4.95 seconds is the same as that covered in the first interval.
 
  • #3
5
0
CompuChip,

I'm not sure I understand what you're saying. What do the variables represent in your equations? I'm sorry if these are silly questions, however I just finished my second day of Physics and am completely new to it (and also very bad at it!).
Thanks.
 
  • #4
berkeman
Mentor
56,647
6,546
CompuChip is showing the equations of motion for a constant velocity. You can break the problem up into the orthogonal velocities in the x and y directions. So his first equation says that x(t) is equal to x(0) = a, plus an offset given by the velocity u multiplied by the time t.

Does that help?
 
  • #5
5
0
berkeman,

I understand that much, however I don't understand how those equations work with my numbers?
 
  • #6
berkeman
Mentor
56,647
6,546
berkeman,

I understand that much, however I don't understand how those equations work with my numbers?
You are given a delta-t and a delta-x and a delta-y. From those numbers and those equations, you can figure out what those constants are (u, a, v, b). With those constants and the next delta-t, you can figure out what the final positions will be after the second delta-t.
 
  • #7
5
0
Thank you, I appreciate your time!
 
  • #8
5
0
I definitely over analyzed the question. All you do is find the change in x and changed in y and add them to the last x and y coordinates. I didn't have to do anything with time or velocity.
 
  • #9
960
0
In this case, yes, but what if the next interval was 6.1 seconds. Profs have bbeen known to do such things, esp physics profs!:smile:


So knowing the velocities is a necessary skill on the third day.
 

Related Threads for: A Coordinates and Interval Question

Replies
4
Views
1K
Replies
3
Views
1K
  • Last Post
Replies
0
Views
756
  • Last Post
Replies
4
Views
1K
Replies
1
Views
1K
Replies
0
Views
4K
Replies
0
Views
1K
  • Last Post
Replies
3
Views
6K
Top