Assuming 25% human efficiency, how many flights of stairs could a 65-kg person climb using the energy in the Snickers bar? Assume a flight of stairs is 2.7 m.
A) 2 flights
B) 5 flights
C) 10 flights
D) 20 flights
First, we need to calculate the energy in a Snickers bar. According to the nutrition label, a regular Snickers bar contains about 250 calories. Let's convert this to Joules:
1 calorie = 4.184 Joules
250 calories x 4.184 Joules = 1046 Joules
Now, let's calculate the potential energy that can be extracted from this Snickers bar for climbing stairs:
Potential energy (PE) = mass x gravity x height
PE = 65 kg x 9.81 m/s^2 x 2.7 m
PE = 1681.305 Joules
Since human efficiency is only 25%, we need to divide the potential energy by 0.25 to find out how much energy can actually be used:
Energy usable = 1681.305 Joules / 0.25
Energy usable = 6725.22 Joules
Now, let's calculate how many flights of stairs can be climbed with this energy:
One flight of stairs = 65 x 9.81 x 2.7 = 1760.95 Joules
Energy usable / energy per flight = 6725.22 Joules / 1760.95 Joules = approximately 3.82
Therefore, a 65-kg person could climb approximately 3 flights of stairs using the energy in a Snickers bar, rounded down to 3 flights.
So, the closest answer choice would be:
A) 2 flights