37. (a) Since τ= dL/dt, the average torque acting during any interval Δtis given by τavg=−LLtfidiΔ, where Liis the initial angular momentum and Lfis the final angular momentum. Thus, 22avg0.800 kg m s 3.00 kg m s1.47 N m1.50s⋅−⋅==−⋅,oravg|| 1.47 N m=⋅. In this case the negative sign indicates that the direction of the torque is opposite the direction of the initial angular momentum, implicitly taken to be positive. (b) The angle turned is 20/2.ttθω α=+If the angular acceleration αis uniform, then so is the torque and = τ/I. Furthermore, ω0= Li/I, and we obtain ()()22223.00kg m s 1.50s1.467 N m 1.50s
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This note was uploaded on 05/17/2011 for the course PHY 2049 taught by Professor Any during the Spring '08 term at University of Florida.