Go Back   Physics Help Forum > College/University Physics Help > General Physics

General Physics General Physics Help Forum

Reply
 
LinkBack Thread Tools Display Modes
Old Feb 22nd 2018, 07:28 AM   #1
Junior Member
 
Join Date: Feb 2018
Posts: 3
Motion

The position of a particle is 6.8t^{3} i + 3 i ^ + 8t^{4} j m . What is the x component of the acceleration at time 3.2 s in unit of ms-2? (t denotes time in second.)

My calculation: ( 6.8*3*3.2^{2} ) / 3.2
Why is it wrong?

Thank you

Last edited by hotk9911; Feb 22nd 2018 at 08:56 AM.
hotk9911 is offline   Reply With Quote
Old Feb 22nd 2018, 07:44 AM   #2
Senior Member
 
Join Date: Apr 2015
Location: Somerset, England
Posts: 987
Well acceleration is the second derivative of time with respect to distance for a start.

3*3.2^{2}
studiot is offline   Reply With Quote
Old Feb 22nd 2018, 07:53 AM   #3
Pmb
Physics Team
 
Join Date: Apr 2009
Location: Boston's North Shore
Posts: 1,557
Originally Posted by studiot View Post
Well acceleration is the second derivative of time with respect to distance for a start.
You just violated the forum rule regarding homework. See
Forum rule
(m)No homework should be posted directly. Workings or any approaches to the questions should be shown to let others know you have made an effort or at least a try. It is to encourage people to learn but not to copy homework.
Must read before posting a problem : please show your attempt!
The Helpers and the staff of the forum have agreed that they won't give a full answer to a problem posted with no attempt (except maybe in some cases). The Helpers are here to help you to understand your weaknesses by going through the asked questions with you and not here to solve your physics problems.
It is imperative to show an attempt to a problem. If you don't know how to start, say it. Helpers will give you a push in the right direction.
I've mentioned this many times but its always been ignored.

Learning physics by doing homework fails when there's no struggle to solve difficult problems. Helping people in such cases is very useful unless the solution is simply given to them. You might think you're helping them by stating the aswer but you're actually hurting them.
Pmb is offline   Reply With Quote
Old Feb 22nd 2018, 07:56 AM   #4
Junior Member
 
Join Date: Feb 2018
Posts: 3
I got it.
It should be (6.8*3*2*3.2) / 3.2=40.8.
Thank you!
hotk9911 is offline   Reply With Quote
Old Feb 22nd 2018, 08:06 AM   #5
Forum Admin
 
topsquark's Avatar
 
Join Date: Apr 2008
Location: On the dance floor, baby!
Posts: 2,442
Originally Posted by Pmb View Post
You just violated the forum rule regarding homework. See
Forum rule


Must read before posting a problem : please show your attempt!

I've mentioned this many times but its always been ignored.

Learning physics by doing homework fails when there's no struggle to solve difficult problems. Helping people in such cases is very useful unless the solution is simply given to them. You might think you're helping them by stating the aswer but you're actually hurting them.
studiot's response is fine by me as he doesn't show how he did it. Call it more of a tease.

Otherwise, yes.
@hotk9911 : What have you been able to do?

-Dan
__________________
Do not meddle in the affairs of dragons for you are crunchy and taste good with ketchup.

See the forum rules here.
topsquark is offline   Reply With Quote
Old Feb 22nd 2018, 08:35 AM   #6
Junior Member
 
Join Date: Feb 2018
Posts: 3
I know the acceleration should be the second derivative but I just miscalculate in my first calculation.
Thanks again for reminding my careless mistake!
hotk9911 is offline   Reply With Quote
Old Feb 22nd 2018, 09:10 AM   #7
Senior Member
 
Join Date: Apr 2015
Location: Somerset, England
Posts: 987
Well I'm comfortable with my assessment of most beginnings and offer advice accordingly.

hotk9911

I thought you made one of those silly slips we all do.

And you need congratulations for actually showing your attempt without being asked.

Hopefully you will get some great advice here in future

Last edited by topsquark; Feb 22nd 2018 at 10:26 PM.
studiot is offline   Reply With Quote
Reply

  Physics Help Forum > College/University Physics Help > General Physics

Tags
motion



Thread Tools
Display Modes


Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
Difference between Einsteins Brownian Motion and Geometric brownian motion. avito009 Physics 5 Nov 6th 2017 09:11 AM
What is the diffrence between between rectilinear motion and translatory motion? StudyMadeEasy Kinematics and Dynamics 3 Feb 21st 2017 01:57 PM
Forces and Motion - Relative Motion Question bonnie.huang Kinematics and Dynamics 1 Jul 7th 2009 03:57 AM


Facebook Twitter Google+ RSS Feed