You are here

a) please see video for steps
b) $0.10 hp$

Giancoli 6th Edition, Chapter 6, Problem 61


Chapter 6, Problem 61 is solved.

View sample solution

Transcript for this Giancoli solution

This is a unit conversion question. And to give us a little perspective we should know that Watts is Newton Meters per second. So this gives us an idea of where to go with our conversions here. We have 550 Foot pounds per second, and we can tell these feet is going to correspond to the meters, and the pounds is going to correspond to the Newtons. So we'll convert each of those. Start by converting the pounds, we have 4.45 Newtons per pound, and then we'll multiply by 1 meter for every 3.28 feet. And this gives an answer of 746 and the units that are left over, are well these pounds here is going to cancel with these pounds, and these feet are going to cancel these feet. So we're going to be left with Newton meters over seconds. So it's 746 Newton meters per second. Which is defined as a Watt, 746 Watts. That's part a. And part b we have a 75 Watt light bulb, in the 6th edition, times 1 Horse power for every 746 Watts, so that's .10 Horse power, is the power of a light bulb. In the 5th edition, this is 100 Watt light bulb. And so you say in the 5th edition, that the answer is .134 Horse powers.