Given data
*The ball is thrown straight upwards at a speed is u = 20 m/s
*The value of the acceleration due to gravity is g = 9.8 m/s^2
*The value of the final velocity of the ball at maximum height is v = 0 m/s
The formula for the time taken by the ball to lose its speed is given by the equation of motion as
[tex]v=u-gt[/tex]Substitute the known values in the above expression as
[tex]\begin{gathered} 0=20-(9.8)t \\ t=2.04\text{ s} \end{gathered}[/tex]