(a) How much work is done in lifting a 1.4-kg book off the floor to put it on a desk that is 0.8 m high? Use the fact that the acceleration due to gravity is g = 9.8 m/s?. (b) How much work is done in lifting a 25-lb weight 5 ft off the ground? SOLUTION (a) The force exerted is equal and opposite to that exerted by gravity, so the force is F = m s = mg = (1.4)(9.8) = dt? |N and then the work done is w = Fd = | J. SE (b) Here the force is given as F = 25 lb, so the work done is w = Fd = 25 · 5 = [ ] ft-Ib. Notice that in part (b), unlike part (a), we did not have to multiply by g because we were given the weight (which is a force) and not the mass of the object.

(a) How much work is done in lifting a 1.4-kg book off the floor to put it on a desk that is 0.8 m high? Use the fact that the acceleration due to gravity is g = 9.8 m/s?. (b) How much work is done in lifting a 25-lb weight 5 ft off the ground? SOLUTION (a) The force exerted is equal and opposite to that exerted by gravity, so the force is F = m s = mg = (1.4)(9.8) = dt? |N and then the work done is w = Fd = | J. SE (b) Here the force is given as F = 25 lb, so the work done is w = Fd = 25 · 5 = [ ] ft-Ib. Notice that in part (b), unlike part (a), we did not have to multiply by g because we were given the weight (which is a force) and not the mass of the object.

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Description: EXAMPLE 1(a) How much work is done in lifting a 1.4-kg book off the floor to put it on a desk that is 0.8 mhigh? Use the fact that the acceleration due to gravity is g = 9.8 m/s?.(b) How much work is done in lifting a 25-lb weight 5 ft off the groun

College Physics

11th Edition

ISBN:9781305952300

Author:Raymond A. Serway, Chris Vuille

Publisher:Raymond A. Serway, Chris Vuille

Chapter1: Units, Trigonometry. And Vectors

Section: Chapter Questions

Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...

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