Science

Operating data are taken on an air turbine. For a particular run, P1 = 8 bar, T1 = 600 K, and P2 = 1.2 bar

Question: Operating data are taken on an air turbine. For a particular run, P1 = 8 bar, T1 = 600 K, and P2 = 1.2 bar. However, the recorded outlet temperature is only partially legible, it could be T2 = 318, 348, or 398 K. Which must it be? For the given conditions, assume air to be an ideal gas with constant CP = (7/2)R. …

Operating data are taken on an air turbine. For a particular run, P1 = 8 bar, T1 = 600 K, and P2 = 1.2 bar Read More »

Suppose that the laptop of Prob. 2.16 is placed in an insulating briefcase with a fully charged battery

Question: Suppose that the laptop of Prob. 2.16 is placed in an insulating briefcase with a fully charged battery, but it does not go into “sleep” mode, and the battery discharges as if the laptop were in use. If no heat leaves the briefcase, the heat capacity of the briefcase itself is negligible, and the …

Suppose that the laptop of Prob. 2.16 is placed in an insulating briefcase with a fully charged battery Read More »

A sculptor and his assistant are carrying a wedge-shaped marble slab up a flight of stairs, as shown in the figure

Question: A sculptor and his assistant are carrying a wedge-shaped marble slab up a flight of stairs, as shown in the figure. The density of the marble is uniform. Both are lifting straight up as they hold the slab completely stationary for a moment. Does the sculptor have to exert more force than the assistant …

A sculptor and his assistant are carrying a wedge-shaped marble slab up a flight of stairs, as shown in the figure Read More »

An object is placed 20.0 cm from a converging lens with focal length 15.0 cm (see the figure, not drawn to scale)

Question: An object is placed 20.0 cm from a converging lens with focal length 15.0 cm (see the figure, not drawn to scale). A concave mirror with focal length 10.0 cm is located 75.0 cm to the right of the lens, (a) Describe the final image—is it real or virtual? Upright or inverted? (b) What …

An object is placed 20.0 cm from a converging lens with focal length 15.0 cm (see the figure, not drawn to scale) Read More »

Bryce Canyon National Park, shown in the accompanying photo, is in dry southern Utah

Question: Bryce Canyon National Park, shown in the accompanying photo, is in dry southern Utah. It is carved into the eastern edge of the Paunsaugunt Plateau. Erosion has sculpted the colorful limestone into bizarre shapes, including spires called “hoodoos.” As you and a companion (who has not studied geology) are viewing the scenery in Bryce …

Bryce Canyon National Park, shown in the accompanying photo, is in dry southern Utah Read More »