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please do parts a-c Hem ework a (Ch l1: Rotational Dynamics) Regin Date: 916 201

ID: 1781588 • Letter: P

Question

please do parts a-c

Hem ework a (Ch l1: Rotational Dynamics) Regin Date: 916 2017 12:00 00 AM-Dae Date: 11172017 11.39.00 PM Ead Date: 12/202013 2 00:00 AM (25%) Problem 4: An ice skater is spinning at Sfeus and han moment of item oras2· Asigamest Status Click bere or detailed view 33% Part (a) Calculate the angular mon emm tn kiloman meters squared per second, of the ice skater spinning at Sin, 100% Problem Status 4 5 6 Completed detsiled vien annRadion Hint eedback:dedcc per feedback , He reduces la fare of renim bs extendzg his arms and meresse h s mammi eftnet a hid tera e of hit mater of 33% Pan nertia (in kilegram meters squased) if his rate of sotation decresses to 35 se i suppose insead he keeps hes arms tn and all wi fictie ofthe ice to slow him to 1-5 rev s what ste magnitude af the 13 erage torque that was exerted, m N·m, iftas take."? Part

Explanation / Answer

(A) w = 5.4 rev/s = 5.4 x 2pi rad/s = 33.93 rad/s

I = 0.52 kg m^2

L = I w = 17.6 kg m^2 / s

(B) Applying angular momentum conservation,

Li = Lf

(0.52)(5.4) = If (1.25)

If = 2.25 kg m^2


(C) now Lf = 0.52x (3.75 x 2pi) = 12.25 kg m^2 / s

Applyng change in angular momentum = torque x time

12.25 - 17.6 = torque (16)

torque = 0.334 N m