NTNUJAVA Virtual Physics Laboratory
Enjoy the fun of physics with simulations!
July 25, 2014, 10:54:09 pm *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with username, password and session length
 
   Home   Help Search Login Register  
Never underestimate others. Never overestimate oneself. ...Wisdom
Google Bookmarks Yahoo My Web MSN Live Netscape Del.icio.us FURL Stumble Upon Delirious Ask FaceBook

Pages: [1]   Go Down
  Print  
Author Topic: Calculation of impact velocity  (Read 12982 times)
0 Members and 1 Guest are viewing this topic. Click to toggle author information(expand message area).
HACKNEYL
Newbie
*
Offline Offline

Posts: 1

«
Embed this message
on: June 05, 2008, 04:40:45 am » posted from:Pretoria,Gauteng,South Africa

Hi All

I enjoyed posts of reaction time calculations & simulations of stopping distance.  My question is:  Two cars drive along.  The front one at 100km/h. He gets hit from behind by a car with speed far exceeding that of the front car.  The brake marks of the car behind measure 65m.  Can we somehow calculate/estimate the speed of the rear car at the point of of impact and at point where he started braking?  Both cars where average size family cars (max 5 persons) only 1 person in rear car.  Had ABS brakes.  Tyres in very good condition. How much impact would road & air temperature as well as tyre temperature have on the result?

Kind regards!
Logged
Fu-Kwun Hwang
Administrator
Hero Member
*****
Offline Offline

Posts: 3053



WWW
«
Embed this message
Reply #1 on: June 05, 2008, 10:12:44 am » posted from:Taipei,T\'ai-pei,Taiwan

Need to know the friction coefficient of tires.
If that car fully stopped without hit the front car, and assume friction coefficient is 1.0, then v2=2*a*s=2*9.8*1.0*65=1274
So estimated speed v=35.7m/s = 128 km/hr.

The speed could be larger, if the coefficient is larger than 1 (normally, yes) and the front car gets hit from behind!
Logged
Pages: [1]   Go Up
  Print  
Never underestimate others. Never overestimate oneself. ...Wisdom
 
Jump to:  


Related Topics
Subject Started by Replies Views Last post
Material strength: an impact experiment
Molecular Workbench
concord 0 8432 Last post August 21, 2005, 11:52:51 pm
by concord
Capacitor Calculation
Electromagnetics
KOKI 4 12094 Last post March 27, 2009, 04:07:15 pm
by lookang
AC Power calculation from current
misc
Fu-Kwun Hwang 6 14515 Last post September 17, 2010, 04:09:36 pm
by Fu-Kwun Hwang
Request : SUN to Earth Energy calculation
Request for physics Simulations
barzivb 6 3279 Last post December 18, 2013, 12:51:58 pm
by TaraLaster
is it possible to eliminate rounding off error in this simulation calculation?
Questions related to EJS
lookang 2 3493 Last post January 26, 2012, 07:36:28 pm
by lookang
Powered by MySQL Powered by PHP Powered by SMF 1.1.13 | SMF © 2006-2011, Simple Machines LLC Valid XHTML 1.0! Valid CSS!
Page created in 0.052 seconds with 22 queries.since 2011/06/15