A projectile is launched at an angle of 20.0° above the horizontal. What is its initial speed if it hits a target that is located a horizontal distance of 175 m from the launch point and 10.5 m above the launch level?

1 answer

S is initial speed
u = S cos 20 forever
so
175 = S cos 20 * t
so t = 175 / (S cos 20)
then the height
10.5 = 0 + S sin 20 * t - 4.9 t^2
10.5 = 175 tan 20 - 4.9 [175^2 / (S^2 cos^2 20)] solve for S