A tennis ball is hit into the air with a racket. When is the ball’s kinetic energy the greatest? Ignore air resistance. A.
when it leaves the racket
B.
just before it reaches the ground
C.
when it reaches its maximum height
D.
when its kinetic energy and potential energy are equal
E.
just before it starts falling downward

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.

Aregular polygon has angkes of size 150° each.how many side has the polygon

An object moves from the position +34m to the position -15m in 15 seconds. what is it's total displacement? what is it's average velocity?