A food Calorie is a kilocalorie in SI units. What would be the speed of a 1,000 kg car traveling such that its kinetic energy is equal to the energy contained in one 250-Calorie jelly doughnut?

Question

Quizplus · Accepted Answer

The energy in one 250-Calorie jelly doughnut is 250 kilocalories, which is equivalent to 250,000 calories. Since 1 calorie is equal to 4.184 joules, the energy in joules is 250,000 * 4.184 = 1,046,000 joules. The kinetic energy (KE) of a car is given by the formula KE = 1/2 mv^2, where m is the mass of the car and v is its velocity. Solving for v gives v = sqrt(2KE/m). Substituting the given values (KE = 1,046,000 joules, m = 1,000 kg) yields v = sqrt(2*1,046,000/1,000) = sqrt(2092) ≈ 46 m/s.

A Food Calorie Is a Kilocalorie in SI Units