Question

Calculate the potential energy required for a 160-lbm person to hike to the top of Long's Peak (14,259 ft) from downtown Boulder, CO (5,430 ft). Compare that to the energy in a McDonald's large Big Mac Meal with chocolate shake.

Answer 1

Given - Body weight - 160-lbm

H2 - 14,259 ft

H1 - 5,430 ft

g - 10 m/s²

Find - Potential energy.

Solution - Potential energy is calculated by the formula - mgh, where m stands for mass, g stands for acceleration due to gravity and h stands for height.

Weight of person in kg - 72.5 kg

Assuming g - 10 m/s²

h = 14259-5430 = 8829 ft in metres = 2691 m

Keeping the values in equation-

P.E. = 72.5*10*2691

P.E. = 1950975 J

P.E. = 1951 kJ.

Energy contained in McDonald's large Big Mac Meal with chocolate shake - 110 calories. This energy is equivalent to 460.2 J or 0.46 kJ.

Hence, potential energy required is 1951 kJ while energy provided by given meal is 0.46 kJ.