An object has a mass of #6 kg#. The object's kinetic energy uniformly changes from #54 KJ# to #150 KJ# over #t in [0, 8 s]#. What is the average speed of the object?

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Answer 1 · 2016-05-30T14:13:06

#sqrt(2)#

Kinetic energy is given by the equation #KE=1/2mv^2# where #m# is the mass and #v# is the velocity (speed)

The starting condition is #54 = 1/2*6v_s^2#
#:.v_s^2=18#

#v_s= 3sqrt(2)#

The end condition is #150 = 1/2*6v_e^2#

#v_e^2 = 50 #

#v_e= 5sqrt(2)#

The average speed is #(v_e-v_s)/2#

#(5sqrt(2)-3sqrt(2))/2 = (2sqrt(2))/2 = sqrt(2)# k/s