It is always good to have an understanding of the magnitude of physical units. In physics, pressure is typically measured in units of pascals (Pa). Categorize each object according to the pressure it exerts when placed on a flat surface. Assume that the bottom of each object is flat. a wooden pencile with a 2- mm-wide lead, balanced on its point a wooden pencile, lying on its side a single penny, lying flat a penny-shaped piece of printer paper a vertical stack of 100 pennies a standard sheet of printer paper call that one pascal of pressure is defined as one newton of force per square meter of area. The pressure exterted by an object can therefore be calculated by P = F / A Where F is the force due to the weight of the object, and A is the area of contact between the object and the surface it is resting on. For example, a 16-oz can of soup weighs about 5 N, and has a cross-sectional area of about 40 cm2 = 0.004 m2. The pressure it would exert on a flat surface is therefore about 5 N / 0.004 m2 = 1250 Pa or about one thousand pascals. The pressure exerted by the other objects can be determined in the same way. First, estimate the weight of each object in newtons (note that one pound is about 5 N). Next, estimate the area of contact in square meters (remember that 1 m2 = 10,000 cm2). The pressure is simply the weight divided by the area. You do not need to do precise calculations to answer this question, only order-of-magnitude estimations.
