An object with a mass of #4 kg# is moving at #7 m/s# over a surface with a kinetic friction coefficient of #2 #. How much power will it take to accelerate the object at #4 m/s^2?

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Answer 1 · 2017-05-15T17:15:50

The power is #=660.8W#

The normal reaction is #N=mg=4gN#

The frictional force

#F_r=mu_k.N#

#F_r=2*4g N#

Let the force necessary to accelerate the object be #F#

Then,

#F=F_r+m*a#

#=8g+4*4#

#=94.4N#

The power is

#P=Fv#

#=94.4*7#

#=660.8W#