angular velocity

**trigunesq** · October 3rd 2009, 04:46 PM

A projectile is launched at 36 m/s and travels 100 m horizontally. If it is to be able to just barely clear a 10 m wall, between what two angles should the projectile be launched with respect to the horizontal?

i have almost no idea what to do!

**mathaddict** · October 3rd 2009, 10:15 PM

Originally Posted by trigunesq

A projectile is launched at 36 m/s and travels 100 m horizontally. If it is to be able to just barely clear a 10 m wall, between what two angles should the projectile be launched with respect to the horizontal?

i have almost no idea what to do!

HI

This is my take on it ..

THe projectile has to satisfies two condition
(1) Travel a range of 100 m
(2) able to clear the wall (maximum height) of 10 m

Range , $R =\frac{u^2\sin 2\theta}{g}$

$100=\frac{36^2\sin 2\theta}{10}$

$\theta=25.25^o$

Now maximum height , $H = \frac{u^2\sin^2 \theta}{2g}$

$10=\frac{36^2\sin^2 \theta}{20}$

$<br /> \theta= 23.13^o<br />$

I don understand what it means by between 2 angles .. but the angle should be > 25.25 .

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