10_InstSolManual_PDF_Part31

10_InstSolManual_PDF_Part31 - 2 5 1 v 1 v 2 2 2 5 1 l 2 l 1...

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10.77. Set Up: The free-body diagram for the crate is given in Figure 10.77. and are the forces exerted by the person above and the person below. The weight of the crate is Figure 10.77 Solve: gives gives and The person above on the stairs applies less force. 10.78. Set Up: Let the direction the wheel is rotating be positive. Use the constant acceleration equations to relate to the motion. Solve: (a) gives (b) gives (c) 10.79. Set Up: The angular momentum of Sedna is conserved as it moves in its orbit. Solve: (a) so When (b) Since is constant the maximum speed is at the minimum distance and the minimum speed is at the maximum distance. (c) Reflect: Since the units of l cancel in the ratios there is no need to convert from AU to m. The gravity force of the sun does work on Sedna as it moves toward or away from the sun and this changes the kinetic energy during the orbit. But this force exerts no torque, so the angular momentum of Sedna is constant. K 1 K 2 5 1 2 m v 1 2 1 2 m v 2
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Unformatted text preview: 2 5 1 v 1 v 2 2 2 5 1 l 2 l 1 2 2 5 1 942 AU 76 AU 2 2 5 154 v l v 2 5 v 1 1 l 1 l 2 2 5 1 4.64 km / s 2 1 76 AU 942 AU 2 5 0.374 km / s l 1 5 76 AU. v 1 5 4.64 km / s, v 1 l 1 5 v 2 l 2 . L 5 m v l u 5 1 v 1 v 2 2 t 5 1 10.47 rad / s 1 2 2 1 125 s 2 5 654 rad 5 104 rev g t 5 I a 5 1 0.956 kg # m 2 21 2 0.0838 rad / s 2 2 5 2 0.0801 N # m a 5 v 2 v t 5 2 10.47 rad / s 125 s 5 2 0.0838 rad / s 2 v 5 v 1 a t t 5 125 s. v 5 0, v 5 10.47 rad / s, I 5 g t a 5 5.00 N # m 5.23 rad / s 2 5 0.956 kg # m 2 a 5 v 2 v t 5 10.47 rad / s 2 2.00 s 5 5.23 rad / s 2 . v 5 v 1 a t 100 rev / min 5 10.47 rad / s a g t 5 I a . F b 5 w 2 F a 5 1960 N 2 588 N 5 1372 N. F a 1 F b 2 w 5 g F y 5 F a 5 1 0.375 1.25 2 w 5 588 N. F a 1 1.25 m 21 cos 45° 2 2 w 1 0.375 m 21 cos 45° 2 5 0. g t 5 y F a F b w x 0.625m 0.375m 0.25m 45 ° Axis 0.25m w 5 mg 5 1960 N. F a F b Dynamics of Rotational Motion 10-31...
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This note was uploaded on 03/06/2009 for the course PHYS 114 taught by Professor Shoberg during the Spring '07 term at Pittsburg State Uiversity.

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