Re: Mechanical Systems Question

*To*: mathgroup at smc.vnet.net*Subject*: [mg14841] Re: Mechanical Systems Question*From*: "Kevin J. McCann" <kevinmccann at Home.com>*Date*: Fri, 20 Nov 1998 02:16:51 -0500*Organization*: @Home Network*References*: <72tqhj$iml@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Sounds like we are working your homework problem. You don't need Mathematica for his one. Look in your freshman physics book. In the first few chapters you will encounter motion under a constant force/acceleration. There you will find VERY simple expressions for x(t) and v(t) which should allow you to solve your problem. Kevin Richard Cooper wrote in message <72tqhj$iml at smc.vnet.net>... >Hi All, > >I am using Mechanical Systems and need help modelling motion where the >velocity of a body is dependent on its distance from a set point. > >For example, I have a body moving in 1D which starts with a speed of 4 >m/s and is subject to a constant but unknown deceleration. The point at >which the body comes to rest must be 25 m from the starting point. > >What is the best way to model this system (and calculate the >decleration)? > >The following might be a good starting point. It needs one more >constraint. > >fixed = 1; >flyer = 2; >start = {0, 0}; >pointOfRest = {0, 25}; > >SetConstraints[ > RotationLock1[1, flyer, fixed, 0], > RelativeY1[2, Point[flyer, 0], 0], > DirectedDistance1[3, Point[flyer, 0], start, {1, 0}, 4T-(a T^2)/2], > Constraint[5, {}, {a, 1}] >] > >Cheers, > >Rich. >