Answer:
Time=3.1 seconds
Explanation:
Given data
Distance S=20 m
Velocity v=10×Sin60°
To find
Time after release
Solution
From equation of simple motion we know that
[tex]S=vt+(1/2)gt^{2}[/tex]
Using the convention that down is positive then
[tex]20m=-10sin60^{o}t+(1/2)(9.8m/s^{2} )t^{2}\\ 20=-8.66t+4.9t^{2}\\ -4.9t^{2}+8.66t+20=0[/tex]
Apply Quadratic formula to solve t
[tex]t=\frac{-(8.66)+\sqrt{(8.66)^{2}+4(-4.9)(20) } }{2(-4.9)}[/tex]
Ignoring the -ve root then we have
t=3.1 seconds
