1. Below are some common foods and their pH values. Which ones are most likely to cause "heartburn"? Explain why you made those choices. soda, 2.0–4.0; lemon juice, 2.00–2.60; tofu, 7.20; tomatoes, 4.0-4.4; cow's milk, 6.40–6.80; tea, 7.20; black coffee, 5.0–5.1; cooked white rice, 6.00–6.70;

In thermodynamics, it refers to the body or assemblage on which attention is focused.

7.40. The cart in Fig. 7.38 has a mass of 2000 kg. It is resting on frictionless wheels on a solid, level surface and encounters no air resistance. At time zero it is standing still, and a jet from a fire hose is used to start it moving. The mass flow rate of the fluid from the fire hose is 100 kg / s, and its velocity relative to fixed coordinates is 50 m/s. The cup on the rear of the cart turns the jet around so that it leaves in the -x direction with the same velocity relative to the cart with which it entered. Calculate the velocity-time behavior of the cart; assume the jet is unaffected by gravity. (This is not a very practical problem, but it is analogous to the more complex and interesting problem of starting a large turbine from rest. All such turbines must be occasionally shut down for maintenance; their starting and stopping behavior is more complex than their behavior running at a steady speed.)

using the table