Computing an equation

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Steven
Steven on 18 Feb 2012
Edited: Azzi Abdelmalek on 16 Oct 2013
I am suppose to find the height and distance traveled by a ball thrown at angle A and a speed v given by:
h(t)=v*t*sin(A)-(1/2)*g*t^2
x(t)=v*t*cos(A)
I am given:
gravity=g=9.81m/s^2
v=10m/s
and the angle A = 35
I know I just plug those into the equations to solve for h(t) and x(t) but I am not given the time "t" so how am I suppose to get t?
I am suppose to compute how high the ball goes, how far it will go, and how long it will take to hit the ground.
PLEASE HELP ME!!!
Part b of the problem asks for "Use the values of v and A given in part a to plot the ball's trajectory; that is, plot h versus x for positive values of h"
How can I do this is we just solved for the exact value of h and x?, we need multiple values of h and x to plot.
  2 Comments
bym
bym on 18 Feb 2012
What do you know about the ball's velocity at the maximum height? What do you know about the ball's height at the time when it hits the ground?
Steven
Steven on 18 Feb 2012
all it gives me is that the velocity is 10 m/s and the gravity and angle that I stated above. I am not given time so how can I figure it out? I know the the answers to the question because they are stated in the back of the book but I don't know how to work my way to the answer. The answers are: ball rises 1.68m high, it will travel 9.58m, and it hits the ground in 1.17s. Those are the answers, hopefully this gives you something to work on.

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Answers (2)

Krishnendu Mukherjee
Krishnendu Mukherjee on 18 Feb 2012
make that two functions in function builder.give the time input as a ramp function,f(t)=t;[may t=0:10] add a scope.find the answer
  3 Comments
Steven
Steven on 18 Feb 2012
The answers to this selected question was posted in the back of my textbook lol
Krishnendu Mukherjee
Krishnendu Mukherjee on 19 Feb 2012
why multiple answer?if u would give a ramp as input.then for different values the different answer would shown as continous signal.you could see.for which value of t maxima is arrising.
why unnecessarily u will make a complicated program?thats why i hv tld that

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Andrei Bobrov
Andrei Bobrov on 18 Feb 2012
syms t
A = 35;
g = 9.81;
v = 10;
h = v*t*sind(A)-(1/2)*g*t^2;
x = v*t*cosd(A);
t_hmax = solve(diff(h,t),t);
hmax = vpa(subs(h,t,t_hmax),5)
x_all = vpa(2*subs(x,t,t_hmax),5)
ADD
xf = matlabFunction(x);
hf = matlabFunction(h);
t2 = linspace(0,2*double(t_hmax),100);
plot(xf(t2),hf(t2))
  2 Comments
Steven
Steven on 18 Feb 2012
Part b of the problem asks for "Use the values of v and A given in part a to plot the ball's trajectory; that is, plot h versus x for positive values of h"
How can I do this is we just solved for the exact value of h and x?, we need multiple values of h and x to plot.
Andrei Bobrov
Andrei Bobrov on 18 Feb 2012
see ADD in my answer

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