An object with a mass of #4 kg# is moving at #7 m/s# over a surface with a kinetic friction coefficient of #3 #. How much power will it take to accelerate the object at #4 m/s^2?

1 Answer
Jan 27, 2018

#952 W#

Explanation:

Clearly,here certain amount of force(#F#) will be required to overcome the frictional force acting at the interface of the object and the surface and then will impart an acceleration(#a#) of #4m/s^2#

Now,here frictional force(#f#) acting is #mu×N# =#mu×mg# i.e #120 N# (#mu# is the coefficient of kinetic friction)

So, from equation of force,we can write,

#F-f=m×a#

Putting the values we get, # F=136 N#

Now,considering that,after application of this force for certain time,the object will attain a velocity(#v#) of #7 m/s# from rest.

So, power required = #F×v# i.e #952 W#