(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A small ball is projected with a speed of 10 m/s at an angle of elevation of p from the top of a vertical pole whose height is 15 m from the level ground. The ball hits the ground at a point whose horizontal distance from the foot of the pole is 20 m . Find the value of p . gravity=10 m/s^2

2. Relevant equations

3. The attempt at a solution

Consider horizontal motion , s=Vx t

20=10 (cos p) t

t=2/(cos p) --1

Consider vertical motion,

15=10 (sin p)(2/(cos p))+1/2 (10)(2\(cos p))^2

15 cos^2 p -20 sin p cos p -20 =0

3 cos 2p - 4 sin 2p=1

5 cos (2p+53.13)=1

2p+53.13=78.46

therefore , p=12.67 degrees

Am i correct ?

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# Homework Help: Projectile motion

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