Concept explainers
(a)
The way that a yo-yo is rolled. There are three forces applied to the yo-yo in three different ways. The yo-yo rests on a horizontal table. It is free to roll, but sliding is resisted. There is a hint to think about the torques about the pivot point, where the yo-yo touches the table. The related diagram is given below:
(b)
The way that a yo-yo is rolled. There are three forces applied to the yo-yo in three different ways. The yo-yo rests on a horizontal table. It is free to roll, but sliding is resisted. There is a hint to think about the torques about the pivot point, where the yo-yo touches the table. The related diagram is given below:
(c)
The way that a yo-yo is rolled. There are three forces applied to the yo-yo in three different ways. The yo-yo rests on a horizontal table. It is free to roll, but sliding is resisted. There is a hint to think about the torques about the pivot point, where the yo-yo touches the table. The related diagram is given below:
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College Physics
- BIO When a gymnast performing on the rings executes the iron cross, he maintains the position at rest shown in Figure P10.85a. In this maneuver, the gymnasts feet (not shown) are off the floor. The primary muscles involved in supporting this position are the latissimus dorsi (lats) and the pectoralis major (pecs). One of the rings exerts an upward fore Fh on a hand as shown in Figure P10.85b. The force Fs is exerted by the shoulder joint on the arm. The latissimus dorsi and pectoralis major muscles exert a total force Fm on the arm. (a) Using the information in the figure, find the magnitude of the force Fm. (b) Suppose an athlete in training cannot perform the iron cross but can hold a position similar to the figure in which the arms make a 45 angle with the horizontal rather than being horizontal. Why is this position easier for the athlete? Figure P10.85arrow_forwardMany of the elements in horizontal-bar exercises can be modeled by representing the gymnast by four segments consisting of arms, torso (including the head), thighs, and lower legs, as shown in Figure P8.15a. Inertial parameters for a particular gymnast are as follows: Note that in Figure P8.l5a rcg is the distance to the center of gravity measured from the joint closest to the bar and the masses for the arms, thighs, and legs include both appendages. I is the moment of inertia of each segment about its center of gravity. Determine the distance from the bar to the center of gravity of the gymnast for the two positions shown in Figures P8.15b and P8.15c. Figure P8.15arrow_forwardFigure CQ10.15 shows a side view of a childs tricycle with rubber tires on a horizontal concrete sidewalk. If a string were attached to the upper pedal on the far side and pulled forward horizontally, the tricycle would start to roll forward. (a) Instead, assume a siring is attached to the lower pedal on the near side and pulled forward horizontally as shown by A. Will the tricycle start to roll? If so, which way? Answer the same questions if (b) the string is pulled forward and upward as shown by B, (c) if the string is pulled straight down as shown by C, and (d) if the string is pulled forward and downward as shown by D. (e) What If? Suppose the string is instead attached to the rim of the front wheel and pulled upward and backward as shown by E. Which way does the tricycle roll? (f) Explain a pattern of reasoning, based on the figure, that makes it easy to answer questions such as these. What physical quantity must you evaluate? Figure CQ10.15arrow_forward
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