November 17th, 2007, 09:25 AM  #1 
Newbie Joined: Nov 2007 From: UK Posts: 5 Thanks: 0  Relative Motion Question
Hi guys, been givin this question for a tutorial and tis really annoying me, not sure what it states. would be brill to get some help... V=velocity Three cars travelling with constand V along a straight road. car A is travelling in same direction as B but 10 mph faster whilst C is travelling in opposite direction with speed of 100mph relative to A. What is the V of C relative to B? (90?) What is the V of B relative to C? (90?) 
November 17th, 2007, 06:49 PM  #2 
Senior Member Joined: Oct 2007 From: Chicago Posts: 1,701 Thanks: 3 
You are correct: A is going 10 mph faster than B, so B is going 10 mph in the other direction (with respect to A). Since C is going 100 mph in the other direction (with respect to A), C is going 100  10 = 90 mph. I would use the positive number +90 with a qualifier of some sort in both cases; If you follow the reference frame, C with respect to B should be 90, but if you follow the statement that "C ... speed of 100 miles relative to A", than C with respect to B should be +90. Bloody physicists are always so imprecise with their use of language. 
November 18th, 2007, 12:27 AM  #3 
Newbie Joined: Nov 2007 From: UK Posts: 5 Thanks: 0 
Ok but the question states A is travelling in the same direction as B.


Tags 
motion, question, relative 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Physics: Projectile Motion/Relative Motion  edwinandrew  Physics  0  February 26th, 2014 03:30 PM 
Help with a relative motion/geometric problem  Optimus  Computer Science  2  February 12th, 2012 11:11 AM 
Relative error question  numMath  Applied Math  4  May 6th, 2011 08:17 PM 
Uniform Relative Motion in 3D  inkliing  Calculus  1  March 2nd, 2010 12:46 PM 
Relative growth question>?  chicagobearsconvulse  Calculus  1  April 28th, 2009 05:05 AM 