After landing on an unfamiliar planet, a space explorer constructs a simple pendulum of length 47.0 cm . The explorer finds that the pendulum completes 91.0 full swing cycles in a time of 125 s. What is the magnitude of the gravitational acceleration on this planet?

Acoal-fired plant generates 600 mw of electric power. the plant uses 4.8 x 10^6 kg of coal each day, and the heat of combustion of coal is 3.3x 10^7 j/kg. the steam that drives the turbines is at a temperature of 300° c, and the exhaust water is at 37° c. (a) what is the overall efficiency of the plant for generating electric power? (b) how much thermal energy is exhausted each day? (c) what is the change in entropy of the universe for this heat engine? (d) using the same heat reservoirs, what is the maximum possible (carnot) efficiency for a heat engine?

Road users moving into your lane, brake lights, and abrupt changes in road surface are a. rare at night b. indicators of potential hazards c. not worth worrying about before you reach them d. no problem for experienced drivers

How is sound energy produced a. vibrating objects b. objects being heated c. temperature differences d. stationary objects