So i know you can solve this either by using vox or voy. i'm getting 3.08s when using vox and 3.14s for voy way. for voy i'm using the formula t=(-2×sin40x24)/-9.8m/s2

The person's horizontal position is given by

and the time it takes for him to travel 56.6 m is

so your first computed time is the correct one.

The question requires a bit of careful reading, and I think there may be a mistake in the problem. The person's vertical velocity at time is

which tells us that he would reach the ground at about . In this time, he would have traveled

But we're told that he is caught by a net at 56.6 m, which would mean that the net cannot have been placed at the same height from which he was launched. However, it's possible that the moment at which he was launched doesn't refer to the moment the cannon went off, but rather the moment at which the person left the muzzle of the cannon a fraction of a second after the cannon was set off. After this time, the person's initial vertical velocity would have been a bit smaller than .

12000j is work done