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us File | A https://edugen.wiley | 07 1 07 2 876 07 6 Halliday, Fundamentals of

ID: 1584886 • Letter: U

Question

us File | A https://edugen.wiley | 07 1 07 2 876 07 6 Halliday, Fundamentals of Physics, 10e PRINTER VERSION BACK NEXT Chapter 07, Problem 021 Your answer is partially correct. Try again A cord is used to vertically lower an initially stationary block of mass M 10 kg at a constant downward acceleration of g/7. When the block has fallen a distance d 3.5 m, find (a) the work done by the cord's force on the block, (b) the work done by the gravitational force on the block, (c) the kinetic energy of the block, and (d) the speed of the block. (Note Take the downward direction positive) (a) Number 2.9E2 (b) Number T[ 2.9E2 (c) Number 49 (d) Number 3.1 Units ni Unit UnitsTm/s Click if you would like to Show Work for this question: en Work SHOW HINT LINK TO TEXT LINK TO SAMPLE PROBLEM VIDEO MINI-LECTURE plus.com/ed ugen/shared assignment/test/aglist.uni?ida asnmt2 13 9275 e here to search

Explanation / Answer

Work done by cord force= Cord force*movement in direction of chord force

/Cord force= Tension T

Force balance mg-T=ma

T=m(g-a) =10*6*9.8/7=84 Newton

Movement is in opposite direction so work done =-ve/

=84*(-3.5)

=-294 Joule

B) Worl done by gravity=mg*d

=10*9.8*3.5

=343 Joule