Rotation Quiz True or False

1. How much more centripetal force is felt by a car going around a 10 m radius turn versus one going around a 30 m radius turn? Assume the cars are traveling at exactly the same speed. -> 9 times more
2. What is the minimum angular acceleration a record must have to start from a stop and make twenty full rotations in six seconds? -> 6.98 rad/s2
3. A hoop of mass 2 kg and radius 0.5 m is hanging from a nail in the wall. How many revolutions does it make in ten seconds when a force of 10 N is applied to it from the bottom of the hoop? -> 500
4. Starting a small aircraft propeller requires the pilot and copilot to manually create an angular acceleration of 7 rad/s2 by spinning the propeller blades. What force do the captain and copilot each need to produce if they grab hold of opposite blades and pull or push in opposite directions? The propeller has a moment of inertia of 30 kg · m2 and is 1.8 m in diameter. -> 466.6 N
5. Tarzan is standing on a cliff ledge before grabbing hold of a vine and swinging down in a circular arc to the valley below. If Tarzan weighs 70 kg, what is the tension in the rope when he reaches the bottom of his swing? -> 0 N
6. A Bōjutsu master is spinning his staff (1.8 m length, 4 kg weight, held in the middle) at a constant speed of 12 rad/s when it collides elastically with an attacking ninja. If the ninja weighs 72 kg and after the collision the staff is spinning at a much slower 1 rad/s, what is the initial speed of the foolish attacker? -> 1.47 m/s
7. Which of these objects (assuming they all have the same mass and are roughly the same size—say the length L of the rods equals the diameter, 2r, of the discs/spheres) will likely have the highest moment of inertia about an axis through their center of mass? -> Throwing hammer
8. One of the theories behind the formation of the moon is that it was ejected from the earth after a fission of cosmic scale3. Let's say the same thing happens to planet Omicron Persei VIII, which has a mass of 8.0×1024 kg, a radius of 9 km, and fully revolves around its axis once every 30 hours. Omicron Persei VIII ejects a 5×1023 kg moon with a 2.5 km radius that spins around once every six hours. What is the new period of rotation of planet Omicron Persei VIII? -> 30.74 hours
9. In a skeeball game, you roll a small ball down a lane until it's popped up at the end by a small ramp. If you roll a skeeball at 2 m/s down the lane, how high should it go after being launched off the ramp? -> 0.20 m
10. In a "walk-the-dog" yo-yo trick, a yo-yo is dropped from about 1 m up and spins at the bottom of its string. How fast will a 3 cm radius (disc-shaped) yo-yo spin when walked? -> 208.8 rad/s

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