BIBI Oefenzitting 3 LO 12-13 Impuls PDF

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Fysica – Fundamenten en Toepassingen bachelor Lichamelijke Opvoeding en Bewegingswetenschappen : 1ste fase Oefeningen 2012-2013

3. Impuls en rotationele dynamica Conceptuele vragen 1. Why should changing the axis of rotation of an object change its moment of inertia, given that its shape and mass remain the same? 2. A beetle sits near the rim of a turntable that is rotating without friction about a vertical axis. The beetle now begins to walk toward the center of the turntable. As a result, does the angular speed of the turntable increase, decrease, or stay the same? Explain.

Oefeningen Opgave 1 (p 290 oef 25) A 92-kg astronaut and 1200-kg satellite are at rest relative to the space shuttle. The astronaut pushes on the satellite, giving it a speed of 0.14 m/s directly away from the shuttle. Seven and a half seconds later the astronaut comes into contact with the shuttle. What was the initial distance from the shuttle to the astronaut? Opgave 2 (p 324 oef 10) A 3.5-inch floppy disk in a computer rotates with a period of 2.00 x 10 -1s. What are (a) the angular speed of the disk and (b) the linear speed of a point on the rim of the disk? (c) Does a point near the center of the disk have an angular speed that is greater than, less than, or the same as the angular speed found in part (a) ? Explain. (Note: A 3.5-inch floppy disk is 3.5 inches in diameter). Opgave 3 (p 324 oef 20) A discus thrower starts from rest and begins to rotate with a constant angular acceleration of 2.2 rad/s². (a) How many revolutions does it take for the discus thrower’s angular speed to reach 6.3 rad/s ? (b) How much time does this take? Opgave 4 (p 327 oef 72) After you pick up a spare, your bowling ball rolls without slipping back toward the ball rack with a linear speed of 2.85 m/s . To reach the rack, the ball rolls up a ramp that rises through a vertical distance of 0.53 m. (a) What is the linear speed of the ball when it reaches the top of the ramp? (b) If the radius of the ball were increased, would the speed found in part (a) increase, decrease, or stay the same? Explain.

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Opgave 5 (p 366 oef 6) At the local playground, a 16-kg child sits on the end of a horizontal teeter-totter (ned: wip), 1.5m from the pivot point. On the other side of the pivot an adult pushes straight down on the teeter-totter with a force of 95 N. In which direction does the teeter-totter rotate if the adult applies the force at a distance of (a) 3.0 m, (b) 2.5 m, or (c) 2.0 m from the pivot? Opgave 6 (p367 oef 19) A fish takes the bait and pulls on the line with a force of 2.2 N. The fishing reel, which rotates without friction, is a cylinder of radius 0.055 m and mass 0.99 kg. (a) What is the angular acceleration of the fishing reel? (b) How much line does the fish pull from the reel in 0.25 s? Opgave 7 (p372 oef 100) When you arrive at Duke’s Dude Ranch, you are greeted by the large wooden sign shown in the figure. The left end of the sign is held in place by a bolt, the right end is tied to a rope that makes an angle of 20.0° with the horizontal. If the sign is uniform, 3.20 m long, and has a mass of 16.0 kg, what are (a) the tension in the rope, and (b) the horizontal and vertical components of the force, F , exerted by the bolt ?

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Opgave 8 (p369 oef 46) A 2.85-kg bucket is attached to a disk-shaped pulley of radius 0.121 m and mass 0.742 kg. If the bucket is allowed to fall, (a) what is its linear acceleration? (b) What is the angular acceleration of the pulley? (c) How far does the bucket drop in 1.50 s? Opgave 9 (p370 oef 69-70) A disk-shaped merry-go-round (Ned: paardemolen) of radius 2.63 m and mass 155 kg rotates freely with an angular speed of 0.641 rev/s. A 59.4-kg person running tangential to the rim of the merry-go-round at 3.41 m/s jumps onto its rim and holds on. Before jumping on the merry-goround, the person was moving in the same direction as the merry-go-round’s rim. What is the final angular speed of the merry-go-round? Does the kinetic energy of the system increase, decrease or stay the same when the person jumps on the merry-go-round? Calculate the initial and final kinetic energies for this system.

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