To determine the maximum height reached by the object, we can use the kinematic equation vf^2 = vi^2 + 2aΔy, where vf is the final velocity (0 m/s at the maximum height), vi is the initial velocity (20 m/s), a is the acceleration due to gravity (-9.81 m/s²), and Δy is the change in height (maximum height – initial height = H – 0 = H). Solving for H, we get H = (vf^2 – vi^2) / (2a) = (0 – 20^2) / (2 * -9.81) ≈ 20.4 meters.

To calculate the time it takes to reach the highest point, we can use the kinematic equation vf = vi + at, where vf is 0 m/s, vi is 20 m/s, a is -9.81 m/s², and t is the time. Solving for t, we get t = (vf – vi) / a = (0 – 20) / -9.81 ≈ 2.04 seconds.

Lastly, to find the time it takes for the object to return to the ground, we double the time it took to reach the highest point. So, the total time of flight is approximately 2.04 * 2 = 4.08 seconds.