Question

A person with a mass of kg climbs four flights of stairs for a total height of 15 meters a)What is their increase of potential energy that b) how much work did they do on that 250 ) Assuming a 25% efficiency of muscles converting food energy into mechanical work , how much energy did they need to consume to climb those stairs ?

Answer 1

Explanation

Part a)

The increase in the potential energy can be calculated as

PE = mgh

Where m is the mass, g is the acceleration due to gravity, and h is the change in height.

So, replacing m = 75 kg, g = 9.8 m/s², and h = 15 m, we get:

PE = (75 kg)(9.8 m/s²)( 15 m)

PE = 11025 J

So, the increase of potential energy was 11025 J.

Part b)

The work done is equal to the change in potential energy, so the work done was 11025 J.

Part c)

If the efficiency is 25%, the amount of energy that they need to consume is equal to the increase in potential energy divided by 0.25, so

11025