267_Dynamics 11ed Manual

267_Dynamics 11ed Manual - plate and wall using cables so...

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Engineering Mechanics - Dynamics Chapter 14 Problem 14-37 A rocket of mass m is fired vertically from the surface of the earth, i.e., at r = r 1 . Assuming that no mass is lost as it travels upward, determine the work it must do against gravity to reach a distance r 2 . The force of gravity is F = GM e m / r 2 (Eq. 13-1), where M e is the mass of the earth and r the distance between the rocket and the center of the earth. Solution: FG M e m r 2 = U 12 r F d = G M e m r 1 r 2 r 1 r 2 d = U 12 GM e m 1 r 2 1 r 1 = Problem 14-38 The spring has a stiffness k and an unstretched length l 0 . As shown, it is confined by the plate and wall using cables so that its length is
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Unformatted text preview: plate and wall using cables so that its length is l . A block of weight W is given a speed v A when it is at A , and it slides down the incline having a coefficient of kinetic friction k . If it strikes the plate and pushes it forward a distance l 1 before stopping, determine its speed at A . Neglect the mass of the plate and spring. Given: W 4 lb = d 3 ft = l 2 ft = k 50 lb ft = l 1.5 ft = k 0.2 = l 1 0.25 ft = a 3 = b 4 = Solution: atan a b = Guess v A 1 ft s = 265...
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