Question

When the ratio of the minimum velocity to the maximum velocity is 1/√2 , the angle of projection of projectile is​

Answer 1

At the time t=0, the projectile has the maximum speed vertically.  At the maximum height the projectile has minimum θ vertical speed.

ϕ= angle of projection

So minimum speed =ucosϕ

Maximum speed =u

Now you can solve it so angle of projection is 45 degrees.

Hope you have a nice day, good luck :)