302_Dynamics 11ed Manual

302_Dynamics 11ed Manual - m located a distance r from the...

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Engineering Mechanics - Dynamics Chapter 14 Problem 14-94 A tank car is stopped by two spring bumpers A and B , having stiffness k A and k B respectively. Bumper A is attached to the car, whereas bumper B is attached to the wall. If the car has a weight W and is freely coasting at speed v c determine the maximum deflection of each spring at the instant the bumpers stop the car. Given: k A 15 10 3 × lb ft = k B 20 10 3 × lb ft = W 25 10 3 lb × = v c 3 ft s = Solution: Guesses s A 1f t = s B 1f t = Given 1 2 W g v c 2 1 2 k A s A 2 1 2 k B s B 2 + = k A s A k B s B = s A s B Find s A s B , () = s A s B 0.516 0.387 ft = Problem 14-95 If the mass of the earth is M
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Unformatted text preview: m located a distance r from the center of the earth is V g = GM e m/r . Recall that the gravitational force acting between the earth and the body is F = G ( M e m/r 2 ), Eq. 13 1. For the calculation, locate the datum at r . Also, prove that F is a conservative force. Solution: V r r G M e m r 2 d = G M e m r = QED F Grad V = r V d d = r G M e m r d d = G M e m r 2 = QED 300...
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