Math Is Fun Forum

Cyprus

Member

Registered: 2015-09-24

Posts: 3

Average Velocity

I started an online assignment that appeared to be simple, and imputed numbers into the formula that gave me the correct answer otherwise, however when I did the exact same work for this question the answer I got is wrong. I've tried it over and over, asked for help, and somehow no one seems to be able to give me an answer thus far, and I don't have the correct answer to compare my work to. Can you please point out my error, and a way to correct it in order to obtain the proper answer? Thank you in advance

Question;
At a time of t seconds, a particle moves a distance of s meters from its starting point, where s=3.7sin(1.7t).
Find the average velocity (correct to four decimal places) between t=1 and t=1+h for the following values of h.

If h=0.1 then the average velocity over the time period [111] equals

Answer;
V= Change in distance/Change in time
V=(3.7sin(1.7 * 1.1)-3.7sin(1.7 * 1))/(1.1-1)
V= 1.0449 m/s

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Average Velocity

Hi;

If that is the right equation then you have made an arithmetic error. Please check your work.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,143

Re: Average Velocity

hi Cyprus

Welcome to the forum.

V= Change in distance/Change in time
V=(3.7sin(1.7 * 1.1)-3.7sin(1.7 * 1))/(1.1-1)

This seems ok to me, so it may just be a mistake doing the calculation.

Please break it down into (1) sin(1.7*1.1)    (2) sin*(1.7*1) and maybe I can see what is going wrong.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

Cyprus

Member

Registered: 2015-09-24

Posts: 3

Re: Average Velocity

Final = 3.7sin(1.7 *1.1) = 0.1207378929
Initial = 3.7sin(1.7 * 1) = 0.1097651031
Final - Initial = 0.1207378929 - 0.1097651031 = 0.0109727898

Change in time = 1.1-1 = 0.1

Change in distance/change in time = 0.0109727898/ 0.1 = 0.109727898, to 4 decimal places -> 0.1097

I'm not sure still where my error is :s

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Average Velocity

Hi;

I get

3.7sin(1.7 *1.1) = 3.535614612355893

3.7sin(1.7 *1) =3.669159798674134

Final - Initial = 3.535614612355893 - 3.669159798674134 = -0.1335451863182411

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Cyprus

Member

Registered: 2015-09-24

Posts: 3

Re: Average Velocity

Oh I see where my error was, left my calculator in degrees and forgot to change it over to radians!
Thank you so much for your time and effort, I greatly appreciate it

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Average Velocity

Hi;

That does happen. Welcome to the forum.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.