An object with a mass of 5 kg is on a surface with a kinetic friction coefficient of  4 . How much force is necessary to accelerate the object horizontally at  3 m/s^2?

May 28, 2017

The force is $= 211 N$

Explanation:

The normal reaction is $N = m g = 5 g$

The frictional force

${F}_{f} = {\mu}_{k} . N$

${F}_{f} = 4 \cdot 5 g = 20 g$

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

Then,

$F - {F}_{f} = m \cdot a$

$F = {F}_{f} + m \cdot a$

$= 20 g + 5 \cdot 3$

$= 211 N$