Pressure cookers have been around for more than 300 years, although their use has strongly declined in recent years (early models had a nasty habit of exploding). How much force (in N) must the latches holding the lid onto a pressure cooker be able to withstand if the circular lid is 28.0 cm in diameter and the gauge pressure inside is 2.80 atm? Neglect the weight of the lid.

Tire gauges for air pressure, as well as most other gauges used in an industrial environment take into account the pressure due to the atmosphere of the Earth. That's why your car gauge reads 0 before you put it on your tire to check your pressure. This is called gauge pressure.   The real pressure within a tire or other object containing pressurized stuff would be a combination of what the gauge reads as well at the atmospheric pressure. If a gauge on a tire reads 13.55 psi, what is the real pressure in the tire in pascals? The atmospheric pressure is 1.01x105 Pa.

A veterinarian uses a hypodermic syringe like the one shown in the figure to inject a horse with a medical solution with a density that is the same as water. The barrel of the syringe has a cross-sectional area of 3.03 x 10-5 m² and before she exerts any force on the plunger, the pressure everywhere in the syringe is 1.00 atm. When she exerts a force with a magnitude of 2.55 N on the plunger, the medical solution squirts horizontally from the needle. Determine the speed of the solution as it leaves the needle. m/s F P1 A₂

One way to administer an inoculation is with a “gun” that shoots the vaccine through a narrow opening. No needle is necessary, for the vaccine emerges with sufficient speed to pass directly into the tissue beneath the skin. The speed is high, because the vaccine (D = 1100 kg/m3) is held in a reservoir where a high pressure pushes it out. The pressure on the surface of the vaccine in one gun is 4.1 x 106 Pa above the atmospheric pressure outside the narrow opening. The dosage is small enough that the vaccine’s surface in the reservoir is nearly stationary during an inoculation. The vertical height between the vaccine’s surface in the reservoir and the opening can be ignored. Find the speed at which the vaccine emerges. (Hint: P1 - P2 = 4.1 x 106 Pa and v1 = 0)