# Cylindrical tank vs conical tank

1. Apr 7, 2015

### Fat Dapper Cat

Hey everyone, I'm new to this site and I figured this would be the best place to ask this question.

We've been using maple to solve two specific problems on the time it would take two tanks to drain. One being cylindrical, and the other conical. They have the same height, the same volume, and the same circular hole at the bottom at the bottom for water to drain out of tank. We found the cylindrical tank drained faster than the conical tank by using Torricelli's law.

So my question is this, based on the shape of these two tanks, why is it that cylindrical tank drains faster?

2. Apr 7, 2015

### Staff: Mentor

Welcome to PF!

Do you have an hypothesis?

3. Apr 7, 2015

### Fat Dapper Cat

Yes, I'm assuming this is because the radius at the base of the conical tank is larger than the that of the cylindrical tank. For ours specifically it was sqrt(3) times larger.

4. Apr 7, 2015

### Staff: Mentor

You are on the right track, but why does that matter?

5. Apr 7, 2015

### Fat Dapper Cat

This would increase the surface area for the conical tank. This must be why our graph's slope decreases at a far faster rate than that of the cylindrical tank.

6. Apr 7, 2015

### Staff: Mentor

Look at it from the other direction: As the tanks empty, which one loses height faster? What impact does that have?