Answer:

Step-by-step explanation:
the unit of length is meter,
so, 80cm=0.8cm, 10cm=0.1m
the length of the rail=
=
The rock's height is increasing in the interval from 0 seconds to 3 seconds.
At time 0 the rock starts moving upward from 52 foot until it reachs 180 foot height (time 3 seconds). Then the rock starts to descend, which means that the height starts to decrease.