Work and Power in Cycling When you ride a bicycle at constant speed, almost all of the energy you expend goes into the work you do against the drag force of the air. In this problem, assume that all of the energy expended goes into working against drag. As we saw in Section 5.7, the drag force on an object is approximately proportional to the square of its speed with respect to the air. For this problem, assume that F α v 2 exactly and that the air is motionless with respect to the ground unless noted otherwise. Suppose a cyclist and her bicycle have a combined mass of 60 kg and she is cycling along at a speed of 5 m/s. 87. Under these conditions, how much power does she expend as she cycles? A. 10 W B. 50 W C. 100 W D. 200 W
Work and Power in Cycling When you ride a bicycle at constant speed, almost all of the energy you expend goes into the work you do against the drag force of the air. In this problem, assume that all of the energy expended goes into working against drag. As we saw in Section 5.7, the drag force on an object is approximately proportional to the square of its speed with respect to the air. For this problem, assume that F α v 2 exactly and that the air is motionless with respect to the ground unless noted otherwise. Suppose a cyclist and her bicycle have a combined mass of 60 kg and she is cycling along at a speed of 5 m/s. 87. Under these conditions, how much power does she expend as she cycles? A. 10 W B. 50 W C. 100 W D. 200 W
When you ride a bicycle at constant speed, almost all of the energy you expend goes into the work you do against the drag force of the air. In this problem, assume that all of the energy expended goes into working against drag. As we saw in Section 5.7, the drag force on an object is approximately proportional to the square of its speed with respect to the air. For this problem, assume that F α v2 exactly and that the air is motionless with respect to the ground unless noted otherwise. Suppose a cyclist and her bicycle have a combined mass of 60 kg and she is cycling along at a speed of 5 m/s.
87. Under these conditions, how much power does she expend as she cycles?
2. Max is swimming across a river that is 42.6 m wide. He can swim at 1.6 m/s and heads 20° to the right of the
vertical. There is a current pushing him more to the right and it has a speed of 0.30 m/s. Determine the time it
takes him to cross the river and find out how far downstream he ends up. Draw the diagram.
Chapter 10 Solutions
College Physics: A Strategic Approach (3rd Edition)
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8.01x - Lect 11 - Work, Kinetic & Potential Energy, Gravitation, Conservative Forces; Author: Lectures by Walter Lewin. They will make you ♥ Physics.;https://www.youtube.com/watch?v=9gUdDM6LZGo;License: Standard YouTube License, CC-BY