You drill a well to a depth of 100-m. Find the difference in water pressure, comparing the top and bottom of the well

Answer 1

the metric unit of pressure is the Pascal (Pa) ... one Newton of force over one square meter

a cubic meter of water has a mass of a thousand kg (a metric ton)
... it exerts a force of 9.81 kN

stacked 100 high, the pressure at the bottom is ... 981 kPa

Answer 2

take a 1 inch area pipe down.
pressure=densitywater*height*9.8N/kg