- #1

Coop

- 40

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**SOLVED**

## Homework Statement

A 23 kg child goes down a straight slide inclined 38∘ above horizontal. The child is acted on by his weight, the normal force from the slide, and kinetic friction. Find the magnitude of the normal force.

## Homework Equations

cos(theta)=adjacent/hypotenuse

## The Attempt at a Solution

I have the answer:

ƩF

_{y}=(F

_{k})

_{y}+ n

_{y}+ w

_{y}

Where F

_{k}is kinetic friction, n is normal force and w is weight

ƩF

_{y}=0+n

_{y}+(-178 N) <- 23 kg * 9.81 m/s^2 = 226 N, 226N * cos(38) = 178 N

Now I know the answer is 180 N (rounded), but for that to be true, ƩF

_{y}would have to equal 0, which means that the F

_{net}would equal 0, which would mean that the kid is in dynamic equilibrium and has an acceleration equal to 0. But why is this true? Wouldn't the kid be accelerating while going down the slide?

Thanks,

Coop

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