How much net work (in joules) is done in accelerating a 1000 kg rocket sled on horizontal frictionless rails from 20 m/s to 40 m/s. Thank you.
2007-05-21 07:07:48 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Physics
Work Done = Change in Kinetic Energy (KE)
KE= 0.5mv^2
change in KE = 0.5*1000*40^2 - 0.5*1000*20^2
= 800 000 - 200 000
= 600 000 Joules
2007-05-21 07:10:41 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Net work equals the change in kinetic energy. Find the change in kinetic energy and that is the work in this situation because the rails are frictionless.
2007-05-21 07:57:57 · answer #2 · answered by msi_cord 7 · 0⤊ 0⤋
_______________________________________________From work energy theorem,
Work 'W'=change in kinetic energy=(1/2)m[v^2 - u^2]
W=(1/2)*1000*[40^2 -20^2]=500*1200=600000 J
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2007-05-21 08:13:23 · answer #3 · answered by ukmudgal 6 · 0⤊ 0⤋