A battery is connected to a small, noisy heater (it makes sound). During a certain period of time after the heater has reached its operating temperature, the battery transfers 10 joules of energy to the heater due to an electric circuit interaction and transfers 0.4 joules of energy to the surroundings due to heat interactions. During that same time period, the heater transfers 8 joules of energy to the surroundings due to heat interactions and transfers 2 joules of energy to the sound receivers due to a sound interaction. What is the efficiency of the heater

Amerry-go-round of radius r, shown in the figure, is rotating at constant angular speed. the friction in its bearings is so small that it can be ignored. a sandbag of mass m is dropped onto the merry-go-round, at a position designated by r. the sandbag does not slip or roll upon contact with the merry-go-round. how would you rank the following different combinations of m and r on the basis of the angular speed of the merry-go-round after the sandbag "sticks" to the merry-go-round from largest to smallest. a) m = 10kg, r = 0.25r b) m = 20kg, r = 0.25r c) m = 10kg, r = 0.50r d) m = 10kg, r = 1.0r e) m = 15kg, r = 0.75r f) m = 40kg, r = 0.25r