# Question

When cruising at 75 mi/h on a highway, a car’s engine develops 45 hp. If this engine has a thermodynamic efficiency of and 1 gal of gasoline has an energy content of 1.3 x 108J, what is the fuel efficiency (in miles per gallon) of this car?

## Answer to relevant Questions

A gram of water (volume of 1.00 cm3) at 100 oC is converted to 1.67 x 103cm3 of steam at atmospheric pres-sure. What is the change in the internal energy of the water (steam)? An ice machine is to convert 10oC water to 0oC ice. If the machine has a COP of 2.0 and consumes electrical power at a rate of 1.0 kW, how much ice can it make in 1.0 h? A child’s swing (a pendulum) has only one natural frequency, f1, yet it can be driven or pushed smoothly at frequencies of f1/2, f1/3, and 2f1. How is this possible? A mass–spring system is in SHM in the horizontal direction. If the mass is 0.25 kg, the spring constant is 12 N/m, and the amplitude is 15 cm, (a) What is the maximum speed of the mass, and (b) Where does this occur? ...The simple pendulum in a tall clock is 0.75 m long. What are (a) The period and (b) The frequency of this pendulum?Post your question

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