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## Homework Statement

A 4.1-kg box is pushed along a horizontal floor by a force of magnitude 21 N at an angle θ = 35° with the horizontal. If the coefficient of kinetic friction between the block and the floor is 0.20, calculate the acceleration of the box. Be careful when calculating the normal force.

## Homework Equations

[tex]\Sigma[/tex]F = ma

F

_{fr}= [tex]\mu[/tex]

_{k}Fn

Fn=mg

## The Attempt at a Solution

Fcos35°- F

_{fr}= ma

21Ncos35° - [tex]\mu[/tex]

_{k}mg = ma

21Ncos35° - 0.20 (4.1 kg) (9.8 m/s

^{2}) = (4.1 kg) a

(17.2021N - 8.036N) / 4.1 kg = a

2.235 m/s

^{2}= a

Is this correct or on the right track?