My Math Forum  

Go Back   My Math Forum > College Math Forum > Applied Math

Applied Math Applied Math Forum


Reply
 
LinkBack Thread Tools Display Modes
July 10th, 2015, 07:13 AM   #1
Senior Member
 
Joined: Sep 2013
From: Earth

Posts: 827
Thanks: 36

Constant Acceleration.

A cyclist travels from A to B, a distance of 240 metres. He passes A at 12m/s, maintains this speed for as long as he can, and then brakes so that he comes to a stop at B. If the maximum deceleration he can achieve when braking is 3m/s, what is the least time in which he can get from A to B?

I've the full solution done my lecturer. But I don't understand it. Can anyone explain this question to me? thanks!
jiasyuen is offline  
 
July 10th, 2015, 09:50 AM   #2
Math Team
 
skeeter's Avatar
 
Joined: Jul 2011
From: Texas

Posts: 2,924
Thanks: 1521

velocity vs time graph ...

skeeter is offline  
July 10th, 2015, 05:18 PM   #3
Global Moderator
 
Joined: May 2007

Posts: 6,756
Thanks: 696

I got the same answer, although I don't understand your method.

Let s be the time before braking. 12s is the distance before braking.
After braking the additional distance traveled is $\displaystyle \int_0^4 (12-3t)dt=24$.

Total distance 12s+24=240, so s = 18 and total time = 22.
mathman is offline  
July 11th, 2015, 03:53 AM   #4
Math Team
 
skeeter's Avatar
 
Joined: Jul 2011
From: Texas

Posts: 2,924
Thanks: 1521

Quote:
Originally Posted by mathman View Post
I got the same answer, although I don't understand your method.
Area under the velocity graph is displacement.

Area under the velocity graph is a trapezoid ...

$h=12$, $b_1=t$, $b_2=t+4$
skeeter is offline  
Reply

  My Math Forum > College Math Forum > Applied Math

Tags
acceleration, constant



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Constant Acceleration jiasyuen Applied Math 5 May 12th, 2015 06:31 PM
Constant acceleration hyperbola Physics 1 March 15th, 2015 10:10 PM
acceleration Mike7remblay Physics 3 February 1st, 2012 06:48 PM
acceleration? imcutenfresa Calculus 5 October 7th, 2009 02:51 PM
Velocity and acceleration imcutenfresa Calculus 2 September 15th, 2009 04:11 PM





Copyright © 2019 My Math Forum. All rights reserved.