# Homework Help: Projectile without air resistance

1. Jan 31, 2010

### xSPARX

1. The problem statement, all variables and given/known data

Consider a projectile without air resistance. Show
that when the range is maximized, it may be given
in terms of the maximum height

2. Relevant equations
R = 4hmax

3. The attempt at a solution
I tried looking upon the equation for the vector R but could not understand where 4h came from. Is the max pertaining to velocity =0 ?

2. Jan 31, 2010

### ideasrule

Write out the equation for range. What's the projectile's speed of launch if its launch angle is optimized? Using this speed and the optimal angle, can you calculate maximum height?

3. Jan 31, 2010

### xSPARX

I appreciate the help for this problem :]

4. Jan 31, 2010

### xSPARX

To find out the projectile speed given that the launch angle is optimized is giving me a hassle because the equation for y or x has time in it. Or am i using the wrong equation?

5. Feb 1, 2010

### aim1732

Yes,the formula for max height does not have x,y or t.

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