22_Dynamics 11ed Manual - Engineering Mechanics - Dynamics...

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Engineering Mechanics - Dynamics Chapter 12 0 v v v d g R 2 y 0 y y 1 Ry + () 2 d = v 2 2 gR 2 1 + 1 0 + = 2 y 0 y + 0 + = v 2 2 y 0 y + 0 + = When it hits, y = 0 v earth 2 gRy 0 0 + = v earth 3.016 km s = * Problem 12-36 When a particle falls through the air, its initial acceleration a = g diminishes until it is zero, and thereafter it falls at a constant or terminal velocity v f . If this variation of the acceleration can be expressed as a = ( g / v f 2 )( v 2 f v 2 ), determine the time needed for the velocity to become v < v f . Initially the particle falls from rest. Solution: d v d t a = g v f 2 v f 2 v 2 = 0 v v 1 v f 2 v 2 d g v f 2 0 t t 1 d = 1 2 v f ln v f v + v f v g v f 2 t = t v f 2 g ln v f v + v f v = Problem 12-37 An airplane starts from rest, travels a distance
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This note was uploaded on 08/16/2011 for the course EGN 3321 taught by Professor Christianfeldt during the Spring '08 term at University of Central Florida.

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