Solve two high school physics application questions, thank you

h=vt+0.5gt^2 (v is the speed 1s before landing), h=35, t=1, and v=30m/s. The speed when landing is v'=v+gt=40m/s

The landing height=v'^2/2g=80m.

The landing time t=v'/g=4s

First find the actual movement height l of the stone within 0.02s (according to the size of the window in the photo and the ratio of the actual size of the window, put the Within 0.02s of exposure, the falling height of the object is converted into the actual falling height),

Find the speed of the object at the end of 0.02s v = l/ 0.02

From the formula v = square root (2gh)

You can find h