I think that it is true, but I'm not exactly sure. :)
Answer:
Explanation:
Given
Speed of ball 
Plane is inclined at an angle 
To win the Game we need to hit the target at
away
Launch angle of ball 
Motion of ball can be considered in two planes i.e. Vertical to the plane and horizontal to the plane
So Net acceleration in vertical plane is 
Range of Projectile is given by

for 





so ball must be launched at an angle of 
私は英語がわかりません sorry pls translate
Answer:
A
Explanation:
The particles of the medium don't travel along with the wave. and I also just did this question