(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A factory worker pushes a 30.0-kg crate a distance of 4.5. along a level floor at constant speed by pushing horizontally on it. The coefficient of kinetic friction between the crate and the floor is 0.25. (a) What magnitude of force must the worker apply?

2. Relevant equations

summation of F x forces = 0

frictional force = coefficient of fric * normal force

3. The attempt at a solution

Hello, my solution is this

since the frictional force and the force of the worker in the x direction are equal,

fric force = 0.25 * 9.8 * 30 kg

fric force = 73.5 NEWTONS

so to find the magnitude of the force that the worker apply, we simply use trigonometric ratios.

cos (30) = 73.5 / r

r = 84.87 newtons

my answer is 84.87, but the answer in the book is 99.2 newtons. can you tell me where did i go wrong? tnx

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# What magnitude of force must the worker apply?

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