Work, Power and EnergyHard
Question
A force acts on a 3 gm particle in such a way that the position of the particle as a function of time is given by x = 3t - 4t2 + t3, where x is meters and t is in seconds. The work done during the first 4 second is-
Options
A.384 mJ
B.168 mJ
C.528 mJ
D.541 mJ
Solution
x = 3t - 4t2 + t3
v =
= 3 - 8t + 3t2
at t = 0 vi = 3 m/s
at t = 4 vf= 19 m/s
According to work energy theorem
w =
mvf2 - 
mvi2
=
m(vf2 - vi2)
(361 - 9)
=
= 528 mJ
v =
= 3 - 8t + 3t2at t = 0 vi = 3 m/s
at t = 4 vf= 19 m/s
According to work energy theorem
w =
mvf2 - mvi2=
m(vf2 - vi2) (361 - 9)=
= 528 mJ
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