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Re: Help on engineering homework
Posted:
Dec 10, 2010 2:04 PM


"Sean de " <sean.dewolski@nospamplease.umit.maine.edu> wrote in message <idtt9r$2eb$1@fred.mathworks.com>... > "Ethan Robinson" <efr450@gmail.com> wrote in message <idtshd$htt$1@fred.mathworks.com>... > > Hello, > > I've been stuck on a matlab problem and can't figure it out, and was hoping to find some help here. > > the problem is as follows: > > "The height and speed of a projectile launched with a speed of vi (initial velocity) at an angle A to the horizontal are given by > > > > h(t)= vi*t*sin(A)0.5*g*(t^2) > > v(t)= sqrt((vi^2)2*vi*g*t*sin(A)+(g^2)*(t^2)) > > > > where g is the acceleration due to gravity. The projectile will strike the ground when h(t)= 0, which gives the time to hit t_hit= 2*(vi/g)*sin(A). > > Suppose that A=30 degrees, vi= 40 m/s and g= 9.81 m/s^2. Use the MATLAB relational and logical operators to find the times when: > > a. The height is no less than 15m > > b. The height is no less than 15m and the speed is simultaneously no greater than 36 m/s. > > c. The height is less than 5m or the pseed is greater than 35 m/s." > > > > I have tried to figure out where to go with it, I know it will involve some if statements with h>15, h>15 and s<36, and h<5 or s>35. Other than that, I'm stumped. > > Thanks, > > Ethan > > Ask you professor? It's not our job to do YOUR homework. Show us what you've done, in code, and be very specific about what isn't working.
He's not available otherwise I would. I realize that, I'm not asking you to do it for me, nor do I want you to. I was just hoping for a tip on how to get going with it. I don't understand the logic behind what to do.



