# Javelin throw and Kinematics

## Main Question or Discussion Point

So my physics project is about making a comic that answers a question (for Grade 5 kids) while answering an underlying kinematics concept. One example question that was given was: what factors produce a home run (max height, range)

So I was wondering about a similar question: What factors would maximize the range of a javelin throw. I was wondering what variables or information would I need to do this? I am new at physics and I am pretty slow so please help me out. Things that I will be looking for would be the d_x for range. The angle it is thrown at, etc and I am hoping on using famous five equations.

Also another thing is need is that that if I use the avg. V_i the players throw the javlein at, do i use sin and cos with the angle to figure out v_x and v_yi.

This is projectile motion right? :)
Sorry, if this is homework...

Sorry, for asking so many question

## Answers and Replies

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Andrew Mason
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So my physics project is about making a comic that answers a question (for Grade 5 kids) while answering an underlying kinematics concept. One example question that was given was: what factors produce a home run (max height, range)

So I was wondering about a similar question: What factors would maximize the range of a javelin throw. I was wondering what variables or information would I need to do this? I am new at physics and I am pretty slow so please help me out. Things that I will be looking for would be the d_x for range. The angle it is thrown at, etc and I am hoping on using famous five equations.

Also another thing is need is that that if I use the avg. V_i the players throw the javlein at, do i use sin and cos with the angle to figure out v_x and v_yi.

This is projectile motion right? :)
Sorry, if this is homework...

Sorry, for asking so many question
This is a projectile motion problem. The range is given by:

$$R = V_0^2\sin{(2\theta_L)/g$$

so immediately you can identify the launch angle that will give you the maximum range for a given initial javelin speed. See:http://hyperphysics.phy-astr.gsu.edu/hbase/traj.html" [Broken]

Also, in order to keep the javelin pointed straight, which will reduce air friction, the thrower could put spin on the javelin (similar to a rifled bullet or a "spiral" football throw) and angle the nose a little off centre. This involves a little more complicated concept of angular motion or spin.

AM

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