Abox slides down a frictionless plane inclined at an angle θ ¸ above the horizontal. the gravitational force on the box is directed

a)vertically.
b)perpendicular to the plane.
c)at an angle θ ¸ below the inclined plane.
d)parallel to the plane in the same direction as the movement of the box.
e)parallel to the plane in the opposite direction as the movement of the box.

Na food processing facility, a spherical container of inner radius r1 5 40 cm, outer radius r2 5 41 cm, and ther- mal conductivity k 5 1.5 w/m · k is used to store hot water and to keep it at 100°c at all times. to accomplish this, the outer surface of the container is wrapped with a 800-w electric strip heater and then insulated. the temperature of the inner surface of the container is observed to be nearly 120°c at all times. as- suming 10 percent of the heat generated in the heater is lost through the insulation, (a) express the differential equation and the boundary conditions for steady one-dimensional heat conduction through the container, (b) obtain a relation for the variation of temperature in the container material by solving the differential equation, and (c) evaluate the outer surface tempera- ture of the container. also determine how much water at 100°c this tank can supply steadily if the cold water enters at 20°c.

Why is metal often used for cooking pan?

Which diagram correctly demonstrates the various forces acting on a ball moving horizontally with some speed?