# I need help coding a human cannonball ignoring air resistance

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### Answers (1)

Jim Riggs
on 12 Mar 2020

Edited: Jim Riggs
on 12 Mar 2020

Assuming zero drag and relatively low muzzle velocity ( acceleration due to gravity = constant), the point-mass trajectory can be described by simple kinematic relationships.

(See derivations in the attached paper)

##### 2 Comments

Jim Riggs
on 13 Mar 2020

The reason that tghe second plot does not stop in the correct place is because you have defined the time span incorrectly for the second case.

You used the same horizontal velocity (v) for both. The second case (for t2) should use v2.

t = (2*v*sind(angle))/9.81; %We have used the equation t = (2*initial_velocity*angle)/g

% in order to calculate the time that it will take for this specific trajectory

% using our chosen values for the velocity and angle

t2 = (2*v*sind(angle2))/9.81;

(Also, you should get in the habit of NEVER hard-coding numeric constants in equations.

Use g=-9.81 or grav = -9.81 Ths will make your code more versitile in the future when you want to run the same calculation, but account for variations in g due to lattitude, (or on Mars, maybe) )

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