Question

Quick Trig Help?

An objects motion is described by the equation : 3cos(pi t ) The displacement, d, is measured in meters. The time, t, is measured in seconds.
A) What is the object's position at t=0 ?
My answer : d = 0?
B) What is the object's maximum displacement from its resting position?
My answer: 3?
C) How much time is required for on oscillation?
My Answer: This I am unsure.. Do we take our d= 0 and then solve?
D) What is the frequency?
My Answer: Unsure again.

Answer 1

If t = 0, wouldn't cos (pi t) = 1 giving displacement a value of 3 * 1 or 3 meters???
How did you get 0 ??

Answer 2

I am curious about that as well

Answer 3

@radar someone else told me 0. But, now I see how they were wrong, and it was 3. cos(0) = 1 ; 3 x 1 = 3 meters. Gotcha.

Answer 4

O.K. Now that max i mum displacement part B. Do you have to account that it is bipolar in that it varies from + 3 to -3?? I not too familiar with a physics type motion and what the definition of displacement in this context.

Answer 5

@radar I am not sure, it doesn't state so on my paper.

Answer 6

Would you look at displacement as the distance it travels for a complete cycle, or just look at its deviation from a central reference point of 0 meters ? ?? I don't know the intent of the problem.

Answer 7

sorry I am so rusty with trig functions. lol

Answer 8

I didnʻt get any coffee this morning and my period 3 teacher has a monotone voice x_x

Answer 9

@radar you are fine, you know more than I do! I do not like trig at all.. I think it wants to know from 0 meters, it states the max. displacement from it's resting position.

Answer 10

@ShadowLegendX Yeah, I've been having that kinda day too.

Answer 11

I am going to look up the term displacement and see it enlightens me.

Answer 12

@radar I was gonna do it for you, but go ahead. :-)

Answer 13

Well i used this link: https://www.google.com/search?q=trignometry+displacement&ie=utf-8&oe=utf-8 and I am still undecided. Sorry, but I am gonna have to have a bowl of chili. Good luck with this and good luck with all your endeavors.

Answer 14

@radar Thanks for the help you were able to give, enjoy your day - and Chili! :-)

Answer 15

I will, I am heating it up now, if I get a definite answer I will reveal it presently I don't know if it is 3 or 6 ??? I bet a multiple choice would have both an answer of 3 and a 6 and one would be wrong!!

Answer 16

@radar Okay! I am not sure what it is, either, but I am gonna try to figure it out. If neither of us get an answer, she will show us the answer. Then, I will let you know. :-)

Answer 17

Please do let me know, I am on here to learn.

Answer 18

@radar As am I! I should know next week, hopefully.