A grandpa travels along the freeway, going 60 mph. A young hotshot travels along the freeway in a car of the same make and model, going 90 mph. Both cars deliver the same fraction of gasoline energy to the drivetrain, and in both cases, almost all of that energy gets converted to thermal energy via drag as follows: (energy dissipated) =(drag force) x (distance traveled).
(i) What two horizontal forces are approximately balanced for a car traveling along the freeway at constant speed?
(ii) Using the formula drag force = (constant) x (speed)n with the appropriate value of n based on class discussion, if both cars make the same trip at their respective speeds, what is hotshot's gas mileage relative to grandpa's? Express as a percentage.

Name three different units of energy used to measure heat and describe what type of situations each is usually used.

Search coils and credit cards. one practical way to measure magnetic field strength uses a small, closely wound coil called a search coil. the coil is initially held with its plane perpendicular to a magnetic field. the coil is then either quickly rotated a quarter-turn about a diameter or quickly pulled out of the field. (a) derive the equation relating the total charge q that flows through a search coil to the magnetic-field magnitude b. the search coil has n turns, each with area a, and the flux through the coil is decreased from its initial maximum value to zero in a time ∆t. the resistance of the coil is r, and the total charge is q = i∆t, where i is the average current induced by the change in flux. (b) in a credit card reader, the magnetic strip on the back of a credit card is rapidly “swiped” past a coil within the reader. explain, using the same ideas that underlie the operation of a search coil, how the reader can decode the information stored in the pattern of magnetization on the strip. (c) is it necessary that the credit card be “swiped” through the reader at exactly the right speed? why or why not?

The diagram shows a series of volcanic island and a hot spot determine the direction of movement of the tectonic plate that for the island