Answer: [tex]21.6\ s[/tex]
Step-by-step explanation:
Given
The initial velocity of the ball is [tex]u=150\ ft\s[/tex]
Angle of projection [tex]\theta=45^{\circ}[/tex]
The time of flight of the ball is given by
[tex]T=\dfrac{2u\sin \theta}{g}\\\\[/tex]
Insert the values
[tex]T=\dfrac{2\times 150\times \sin 45^{\circ}}{9.8}\\\\T=\dfrac{212.132}{9.8}\\\\T=21.6\ s[/tex]