Question

PRACTICE IT Use the worked example above to help you solve this problem. A merry-go-round modeled as a disk of mass M 7.50x 101 kg and radius R 2.40 m is rotating in a horizontal plane about a frictionless vertical axle (see figure) (a) After a student with mass m 84.0 kg jumps onto the merry-go-round, the system's angular speed decreases to 2.10 rad/s. If the student walks slowly from the edge toward the center, find the angular speed of the system when she reaches a point 0.530 m from the center. rad/s 6.1264607 (b) Find the change in the system's rotational kinetic energy caused by her movement to the center. (c) Find the work done on the student as she walks to r 0.530 m. EXERCISE HINTS: GETTING STARTED I M STUCK Use the values from the PRACTICE IT section to answer this exercise. (a) Find the angular speed of the merry-go-round before the student jumped on, assuming the student didn't transfer any momentum or energy as she jumped on the merry-go-round. rad/s (b) By how much did the kinetic energy of the system change when the student jumped on? Notice that energy is lost in this process, as should be expected, since it is essentially a perfectly inelastic collision KE,-KE Need Help? Read it Submit Answer Save Progress Practice Another Version
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Answer 1

R- DisK ma M = 754, Kadius udent ma D = 12-75 x(- 216 2 2 MR M. dyk = Ahuden Znitia alar nmamunk thi (hh u 457.93 X , - j6162 Lutien shudonh noes o53 m 2- 84xl053 23.6 2- fal aulan momerntunm Angular nsmentum conweol Ao 9612.2 216+23 - 410 Yuds. change 2. 2 (3x(401)2-j X yS7 92 x(2 16 ol o 916 4 J - AKEuden p ^^"i Work done 2 189 74-533.6/ 3y3.9 J