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

A 45.0 kg child is in a swing that is attached

to ropes 1.90 m long.

The acceleration of gravity is 9.81 m/s2 .

Find the gravitational potential energy as-

sociated with the child relative to the child’s

lowest position under the following condi-

tions:

a) when the ropes are horizontal.

Answer in units of J.

2. Relevant equations

Height of a pendulum:

h=L(1-cos(θ))

Potential Energy

PE=mgh

3. The attempt at a solution

So first I found the height of the swing at a horizontal position which I assumed is as at 90°.

h=L(1-cos(θ))

2.75m=1.9(1-cos(90))

Then I used that height and put it into the formula for potential energy

PE=mgh

1213.99 J? = (45)(9.81)(2.75)

but the online homework interface I have to use to input my answer tells me this isn't correct. I was wondering if maybe my answer isn't in Joules, do I need to convert something. Any help would be greatly appreciated.

I realized my problem, i had my calculator in radian's sorry for the stupid question, I'd delete the question if i can find out how

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# Homework Help: Finding Potential Energy of a Swing When the Ropes Are Horizontal?

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