If a donut contains 250 food calories,express the kinetic energy of a 1200-kg car speeding along the highway at 65 mph in units of donuts.

Question

Quizplus · Accepted Answer

To solve this problem, we need to use the formula for kinetic energy: KE = 0.5mv^2, where m is the mass of the car and v is its velocity. Converting the velocity to meters per second (m/s), we get:

v = 65 mph = (65 mi/hr)(1.609 km/mi)(1000 m/km)/(60 min/hr)(60 s/min) 
= 29.05 m/s

Now, plugging in the given values:

KE = 0.5(1200 kg)(29.05 m/s)^2 
= 502914 J

To express this energy in donuts, we divide by the energy content of one donut:

KE in donuts = 502914 J / 250 cal/donut * 4.184 J/cal
= 480 donuts (rounded to the nearest whole number)

Therefore, the correct answer is C) 0.48.

If a Donut Contains 250 Food Calories,express the Kinetic Energy