The Three Gorges Dam spanning the Yangtze River in China was the largest dam in the world when it was completed in 2012. The top of the dam is $185 \mathrm{~m}$ above sea level but when filled the water level is $175 \mathrm{~m}$ above sea level.

a. What would be the pressure at the bottom of the dam?

b. Dam design is a very complicated topic, but to simplify it a bit we can just look at the pressure the water exerts at the dam bottom and the pressure the concrete exerts and compare the two numbers. Assuming the dam is $115 \mathrm{~m}$ thick at the bottom and $40 \mathrm{~m}$ thick at the top, what is the pressure per unit width at the bottom due to the weight of the concrete? Is that enough to hold back the water?