My Math Forum  

Go Back   My Math Forum > College Math Forum > Calculus

Calculus Calculus Math Forum


Reply
 
LinkBack Thread Tools Display Modes
June 1st, 2009, 01:10 AM   #1
Newbie
 
Joined: Mar 2009

Posts: 20
Thanks: 0

Using the definite integral to find motion

Hi,

The question I've been asked to do is to find s(4) of an object moving in a straight line, given a(t) = , s(0) = 2, v(0) = 3.

Am I supposed to use a(t) to solve the equation? All the examples I've seen is just plugging numbers into the equation .

Assuming I don't have to use a(t), my working is , giving -85.4. Is this correct?
funsize999 is offline  
 
June 1st, 2009, 03:55 AM   #2
Senior Member
 
Joined: Dec 2008

Posts: 251
Thanks: 0

Re: Using the definite integral to find motion

To solve the problem, we must remember that



and therefore that



In our case, the object has an acceleration function different from that of an object tossed in the air. Integrating twice, we obtain



All that remains is to find the values of and and evaluate .
Scott is offline  
June 1st, 2009, 01:50 PM   #3
Newbie
 
Joined: Mar 2009

Posts: 20
Thanks: 0

Re: Using the definite integral to find motion

Thanks for the reply.

Another question, for numerical integration, for between 2 and 5, I've drawn a table of values for the f(x) of each (with h = 0.5). Some of these values are negative; would I take the absolute values of these? i.e. my table looks like this

x | f(x)
2 | 0.90...
2.5 | 0.59...
3 | 0.14....
3.5 | -0.35...
4 | -0.76....
4.5 | -0.97....
5 | -0.95...

so should I take the absolute value of f(x) 3.5 to 5?
funsize999 is offline  
June 1st, 2009, 02:36 PM   #4
Senior Member
 
Joined: Dec 2008

Posts: 251
Thanks: 0

Re: Using the definite integral to find motion

In calculating definite integrals, no. Area below the -axis is counted as negative area.
Scott is offline  
Reply

  My Math Forum > College Math Forum > Calculus

Tags
definite, find, integral, motion



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Find the integral - definite sachinrajsharma Calculus 1 June 18th, 2013 11:38 PM
definite Integral panky Calculus 1 December 10th, 2012 10:36 PM
definite integral binny Calculus 11 May 28th, 2011 11:12 AM
Definite Integral Mandy85 Calculus 1 January 6th, 2009 01:55 PM
What happens if there's one integral of motion? dbrogioli Real Analysis 0 March 31st, 2008 04:45 AM





Copyright © 2018 My Math Forum. All rights reserved.