An object has a mass of #9 kg#. The object's kinetic energy uniformly changes from #135 KJ# to # 36KJ# over #t in [0, 6 s]#. What is the average speed of the object?

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Answer 1 · 2016-04-19T16:47:08

I don't produce any number as the result, but here is how you should approach.

#KE = 1/2 mv^2#

Hence, #v = sqrt((2KE)/m)#

We know #KE = r_k *t+c# where #r_k = 99KJs^(-1)# and c = #36KJ#

So the rate of change of velocity #r_v# is related to the rate of change of kinetic energy #r_k# as:

#v = sqrt((2r_k*t +2c)/m) #

now, average velocity should be defined as:

#v_"avg" = (int_0^t vdt)/t= 1/5int_0^5 sqrt((2r_k*t +2c)/m) dt#