As a Christian scientist, Dr. Bohlin is open to examining the theories of both young-earth and old-earth scientists to explain what we can observe today. The Grand Canyon provides an excellent venue to consider the theories of both groups on how the geological layers were formed and when this occured.
If the door is already attached, swing it open and closed to see how much inertia it has. An average hollow-core door usually weighs around 25 to 30 pounds, so if you can lift or swing the door with minimal effort, it is probably hollow-core. Solid-core doors are usually 25 to 30 pounds heavier than their hollow counterparts, so if the door has some heft to it, it's probably solid-core.
Depending on the design, you can know in advance how many turns are going to have to be unwound. Lifting a 7-foot door by winding a cable on a 4-inch diameter (about 1 foot circumference) drum requires about 7 turns, plus one extra turn to maintain cable tension at the top-of-travel.f we pessimistically assume the 10-by-7-foot door has a weight of 350 pounds, this implies a torque of 350 pounds on a 2-inch radius, that is, 700 inch-pounds, or 58 foot-pounds. Each of the two springs should be exerting slightly less than half of the balancing torque, or 29 foot-pounds.