You have seen dogs shake to shed water from their fur. The motion is complicated, but the fur on a dog’s torso rotates back and forth along a roughly circular arc. Water droplets are held to the fur by contact forces, and these forces provide the centripetal acceleration that keeps the droplets moving in a circle, still attached to the fur, if the dog shakes gently. But these contact forces—like static friction—have a maximum possible value. As the dog shakes more vigorously, the contact forces cannot provide sufficient centripetal acceleration and the droplets fly off. A big dog has a torso that is approximately circular, with a radius of 16 cm. At the midpoint of a shake, the dog’s fur is moving at a remarkable 2.5 m/s. a. What force is required to keep a 10 mg water droplet moving in this circular arc? b. What is the ratio of this force to the weight of a droplet?
You have seen dogs shake to shed water from their fur. The motion is complicated, but the fur on a dog’s torso rotates back and forth along a roughly circular arc. Water droplets are held to the fur by contact forces, and these forces provide the centripetal acceleration that keeps the droplets moving in a circle, still attached to the fur, if the dog shakes gently. But these contact forces—like static friction—have a maximum possible value. As the dog shakes more vigorously, the contact forces cannot provide sufficient centripetal acceleration and the droplets fly off. A big dog has a torso that is approximately circular, with a radius of 16 cm. At the midpoint of a shake, the dog’s fur is moving at a remarkable 2.5 m/s. a. What force is required to keep a 10 mg water droplet moving in this circular arc? b. What is the ratio of this force to the weight of a droplet?
You have seen dogs shake to shed water from their fur. The motion is complicated, but the fur on a dog’s torso rotates back and forth along a roughly circular arc. Water droplets are held to the fur by contact forces, and these forces provide the centripetal acceleration that keeps the droplets moving in a circle, still attached to the fur, if the dog shakes gently. But these contact forces—like static friction—have a maximum possible value. As the dog shakes more vigorously, the contact forces cannot provide sufficient centripetal acceleration and the droplets fly off. A big dog has a torso that is approximately circular, with a radius of 16 cm. At the midpoint of a shake, the dog’s fur is moving at a remarkable 2.5 m/s.
a. What force is required to keep a 10 mg water droplet moving in this circular arc?
b. What is the ratio of this force to the weight of a droplet?
A puck of mass m=0.075 kgis moving in a circle on a horizontal frictionless surface. It is held in its path by a massless string of length L=0.42 m. The puck makes one revolution every t=0.35 s
a)What is the magnitude of the tension in the string, in newtons, while the puck revolves?
b)
A puck of mass m=0.095 kg is moving in a circle on a horizontal frictionless surface. It is held in its path by a massless string of length L=0.63 m. The puck makes one revolution every t=0.65 s.
1. What is the magnitude of the tension in the string, in newtons, while the puck revolves?
2. The string breaks suddenly. How fast, in meters per second, does the puck move away?
A small block with mass 0.0400 kg slides in a vertical circle of radius R = 0.500 m on the inside of a circular track. During one of the revolutions of the block, when the block is at the bottom of its path, point A, the normal force exerted on the block by the track has magnitude 3.95 N. In this same revolution, when the block reaches the top of its path, point B, the normal force exerted on the block has magnitude 0.680 N. How much work is done on the block by friction during the motion of the block from point A to point B?
Chapter 6 Solutions
College Physics: A Strategic Approach Technology Update, Books a la Carte Edition & Modified Mastering Physics with Pearson eText -- ValuePack Access . Chapters 1-16 and 17-30 (3rd Edition)
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