Physics question - struggling

First, split the problem into two halves: the time the ball takes to reach its maximum height and the time it takes for the ball to fall from its maximum height to the ground.

1. Time to reach maximum height
You know that at its maximum height the ball must have a final velocity (v) of 0 m/s and the ball has initial velocity (u) of 9.1 m/s, so you can use 't = (v-u)/g', where g is the negative acceleration due to gravity (-9.81 m/s^2). This will give you the time it takes for the ball to reach its maximum height.

2. Time to fall from maximum height to the ground
You know that its maximum height above the ground is 1.4 m + the height gained by the ball in step 1. The time taken for the ball to fall from its maximum height to its original height of 1.4m will be the same as the time value calculated in part 1 as acceleration due to gravity is constant. To calculate the time taken for the ball to fall the final 1.4m, you first need to find out the velocity of the ball when it is 1.4 m above the ground. Use 'v = u + gt', where u = the velocity of the ball at its maximum height (0 m/s), g = acceleration due to gravity (9.81 m/s^2) and t = time value calculated in part 1. Using this value of v, you can calculate the time taken for the ball to fall the final 1.4 m using 's = ut + 0.5gt^2', where s = 1.4 m, u = the value of v you just calculated and g = acceleration due to gravity (9.81 m/s^2).

Now just add all three time values together and you should have your answer