5. Identify three units used to express pressure. b. Convert one atmosphere to millimeters of

## Step 1<br />Pressure is a physical quantity that measures the force exerted per unit area. It is a fundamental concept in physics, particularly in the study of fluid mechanics and thermodynamics. The units used to express pressure are derived from the basic definition of pressure.<br /><br />## Step 2<br />The three common units used to express pressure are:<br />### **Atmosphere (atm)**<br />This is a unit of pressure based on the average atmospheric pressure at sea level. It is defined as the force per unit area exerted by the weight of the atmosphere at sea level.<br /><br />### **Millimeter of Mercury (mmHg)**<br />This unit is based on the height of a column of mercury that exerts a certain pressure. It is commonly used in medicine and meteorology.<br /><br />### **Pascal (Pa)**<br />This is the SI unit of pressure. It is defined as one newton per square meter. It is a widely used unit in scientific research and engineering.<br /><br />## Step 3<br />To convert one atmosphere to millimeters of mercury, we use the conversion factor that 1 atm is approximately equal to 760 mmHg. This conversion is based on the fact that the average atmospheric pressure at sea level is equivalent to the pressure exerted by a 760 mm high column of mercury.