**Learning objectives**

- Compute divergence by thinking about mass flow into a box
- Use the divergence theorem

**Before class**

- Read Hughes-Hallett sections 20.1 and 20.2
- Ponder Hughes-Hallett problems: 20.1: 4, 6, 13, 20; 20.2: 3.
- Post to Piazza
- Write solutions to problems 18.4: 8, 24; 19.1: 12; 19.2: 4 to turn in at the beginning of class.
- Complete HW12 on WeBWork

**In class**

- Prepare for Thursday’s test
- Work through section 1 of document on fluid mechanics
- Problems on divergence and divergence theorem