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

You are dragging a 110 kg trunk across a floor at a constant velocity with horizontal force of 380 N. A friend decides to help by pulling on the trunk with a force of 150 N [up]. Will this help? Calculate the force required to pull the trunk at a constant velocity to help you decide.

2. Relevant equations

μ_{k}= F_{k}/F_{N}

F_{g}= m × g

3. The attempt at a solution

I found the coefficient of kinetic friction (μ_{k}) to be 0.35.

I'm confused by what it means by "will this help?". Wouldn't it help because your friend is reducing the F_{N}(force normal) on the trunk? I found force required to pull the trunk at a constant velocity is 377.3 N (F_{k}) using the equation:

μ_{k}= F_{k}/F_{N}

= 0.35 x 1078 N

= 377.3 N.

Now, when your friend is pulling the trunk upwards wouldn't the Force normal decrease to 928 N [up] because 1078 N - 150 N? So would the force required be

F_{k}/ F_{N}= 324.8N?

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# Homework Help: Force required to pull trunk across floor

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