30. (a) calculate the rate of heat conduction through house walls that are 13.0 cm thick and that have an average thermal conductivity twice that of glass wool. assume there are no windows or doors. the surface area of the walls is 120m2 and their inside surface is at 18.0ºc, while their outside surface is at 5.00ºc. (b) how many 1-kw room heaters would be needed to balance the heat transfer due to conduction?

The earth exerts a gravitational force of 500 n on amy. what is amy’s mass in kg?

An astronaut in space cannot use a scale or balance to weigh objects because there is no gravity. but she does have devices to measure distance and time accurately. she knows her own mass is 77.4 kg , but she is unsure of the mass of a large gas canister in the airless rocket. when this canister is approaching her at 3.50 m/s , she pushes against it, which slows it down to 1.30 m/s (but does not reverse it) and gives her a speed of 2.60 m/s . what is the mass of the canister?

How many meters will a car travel if its speed is 45 m/s in an interval of 11 seconds? question 2 options: a) 450 meters b) 495 meters c) 4.09 meters d) 498 meters