Physics - Kinematics Question with Solution | TestHub

The two crossings are symmetric about the top, so the ball takes $2$ s from the $25$ m level to the highest point; its speed at $25$ m is $u_1=g(2)=20$ m/s. Then $v^2=u^2-2gh$ gives $400=u^2-2(10)(25)$, so $u^2=900$ and $u=30$ m/s. Option C.