It takes the moon about 27 days to revolve on its axis.
One of the equations of gravity is this:

Where v = final velocity which is 7m/s
u = initial velocity which is 0 for objects falling from a height
g = acceleration due to gravity and it is approximately 10m/s^2. It's a constant so pretty much remember this number. It's positive since the work being done is caused by gravity (in other words, it's falling down). It can also be negative if the work being down is against gravity (in other words, it's going up)
h = height of object
Substitute for the values and you should have something like this



Answer:
1) Periodically check the no stop or NDL time on their computers
2) The dive computer planning mode can be used if available
3) Make use of a dive planning app
4) Check data from the RDP table or an eRDPML
Explanation:
The no stop times information from the computer gives the no-decompression limit (NDL) time allowable which is the time duration a diver theoretically is able to stay at a given depth without a need for a decompression stop
The dive computer plan mode or a downloadable dive planning app are presently the easiest methods of dive planning
The PADI RDP are dive planners based on several years of experience which provide reliable safety limits of depth and time.