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Topic: Help on engineering homework
Replies: 9   Last Post: Dec 11, 2010 9:34 PM

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 Ethan Robinson Posts: 5 Registered: 12/10/10
Help on engineering homework
Posted: Dec 10, 2010 1:46 PM
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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

Date Subject Author
12/10/10 Ethan Robinson
12/10/10 Sean
12/10/10 Ethan Robinson
12/10/10 Paulo
12/10/10 Andy C.
12/10/10 Ethan Robinson
12/10/10 ImageAnalyst
12/10/10 Rick Rosson
12/11/10 Ethan Robinson
12/11/10 Raymond

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