An object has a mass of #6 kg#. The object's kinetic energy uniformly changes from #120 KJ# to # 36 KJ# over #t in [0, 4 s]#. What is the average speed of the object?

1 Answer
May 18, 2016

Answer:

#bar v =159.178#

Explanation:

Calling #t_1=0, t_2= 4,E_1=120000,E_2=36000,m=6#
interpolating the kinetic energy #e# we get
#e = E_1+((E_2-E_1)/(t_2-t_1))(t-t_1)# but #e = 1/2mv^2#
also
#v = sqrt(2e/m)#. Average speed is obtained calculating
#bar v =( int_{t_1}^{t_2}v dt)/(t_2-t_1) = 159.178#