   Chapter 5, Problem 52P

Chapter
Section
Textbook Problem

While running, a person dissipates about 0.60 J of mechanical energy per step per kilogram of body mass. If a 60.-kg person develops a power of 70. W during a race, how fast is the person running? (Assume a running step is 1.5 m long.)

To determine
How fast the person is running.

Explanation

Given Info:

The mechanical energy dissipated per step per kilogram of body mass. is 0.60J .

The mass of the person is 60.0kg .

The power developed by the person is 70.0W

The running step is equal to 1.5m .

Consider ΔN is the number of steps taken by the person in a time Δt .

According to equation for power,

P=WtΔt

• Wt is the total work done
• Δt is the change in time

Thus,

P=WtΔt=Wsm(ΔNΔt)

• Ws is the work per step per mass
• m is the mass of the person

On re-arranging,

ΔNΔt=PWsm       (I)

The running speed of the person is,

v=ΔN

Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started 