A hot air balloon weighing 30N is tied to the ground by astring to prevent from floating off the ground. The volume of the balloon is 20m and the density of air is 1.3kg. what is the upthrust acting on the balloon take g=10ms and whats the force exercted by the rope on the balloon?

Which statement best describes how private industry decides where to spend the money on research and development

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.

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?