Answer:
1.61 second
Step-by-step explanation:
Angle of projection, θ = 53°
maximum height, H = 7.8 m
Let T be the time taken by the ball to travel into air. It is called time of flight.
Let u be the velocity of projection.
The formula for maximum height is given by
![H = (u^(2)Sin^(2)\theta )/(2g)](https://img.qammunity.org/2020/formulas/physics/high-school/dyxplnmpc3bhrf6t2x1lepl4k8jqm8v2jh.png)
By substituting the values, we get
![7.8= (u^(2)Sin^(2)53 )/(2* 9.8)](https://img.qammunity.org/2020/formulas/physics/college/mkuoa81gh3sxazn3sd8zskmi6ntkgzw05g.png)
u = 9.88 m/s
Use the formula for time of flight
![T = (2uSin\theta )/(g)](https://img.qammunity.org/2020/formulas/physics/college/ihv2odvk2ff81h3jd4q4ih2nze6mnkdluj.png)
![T = (2* 9.88* Sin53 )/(9.8)](https://img.qammunity.org/2020/formulas/physics/college/slz2mn0aqx7jncjcieqxwsjm4zrl9lttyq.png)
T = 1.61 second