Download Aims and Objectives: Provide an opportunity for students to

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PRACTICAL EXERCISE 3 PROJECTILES
Aims and Objectives: Provide an opportunity for students to design and implement a more
substantial software system (than those produced for parcticals 1 and 2) that, in addition,
requires use of methods contained in the Math class found in the Java API.
1. REQUIREMENTS
Produce a computer program, written in the Java programming language, which determines
the distance travelled by a projectile (projected from the ground) given:
1. Velocity at launch (u), and
2. Launch angle (angle of elevation) above the horizontal (A).
Assume the following:
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The angle of elevation is given in degrees and is in the range of 0 to 90.
Start velocity is given as a positive number.
Acceleration due to gravity (g) is equivalent to 10m/s^2.
The effect of air resistance can be ignored.
Note also that to solve the above we must carry out the following steps.
1. Calculate the vertical and horizontal components of u (the launch velocity) using the
following trigonometric identities:
2. Vertical component of launch velocity
(Vu) = u x sinA
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3. Horizontal component of launch velocity (Hu) = u x cosA
4. Calculate the time (t) taken for the body to return to the ground using the identity:
5. t = (2 x Vu)/a
where a (deceleration due to gravity) is equivalent to g (10m/s^2 in this case).
6. Calculate distance (s) traveled from the identity:
7. s = Hu x t
2. EXAMPLE
A body is projected with a velocity of u = 200 m/s at an angle of elevation A = 30 degrees
above the horizontal. Determine the distance travelled by the projectile.
Vu = 200 x sin30 = 100 (m/s)
Hu = 200 x cos30 = 173.2 (m/s)
t = {2 x 100)/10 = 20 (s)
s = 20 x 173.2051 = 3464.1 (m)
3. REPORT
You should prepare a report comprising the following sections:
1. Requirements: Summary of the above requirements.
2. Analysis and Design: A short (one paragraph) description of your analysis of the
problem including a Class Diagram outlining the class structure for your proposed
solution and a set of "summary tables". Detailed designs for the methods you intend
to include supported by a Nassi-Shneiderman chart for each.
3. Implementation: Your Java source files.
4. Testing: A set of appropriate arithmetic test cases (presented in tabular form) and the
output from your program as a result of running these test cases.
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4. MARK SCHEME
90% of the marks will be distributed evenly between: Analysis and Design; Implementation;
and Testing. The remaining 10% will be awarded for "overall presentation".
5. INTERESTING LINKS
1. Projectile Motion (Drew Dolgert, Michael Fowler).
Created and maintained by PIUS NYAANGA Last updated 30 June 2011