- #1

jforce93

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## Homework Statement

Okay, so I'm using the online Giancoli physics thing for AP Physics C summer work (see: "([PLAIN]http://wps.prenhall.com/esm_giancoli_physicsppa_6"[/URL]. I think my way of doing it is correct, but the online checker says I'm wrong.

The question: "A pendulum has a mass of 3.2 kg, a length of 1.5 meters, and swings through a (half)arc of 17 degrees. To the nearest tenth of a Joule, what is its maximum kinetic energy of the pendulum?"

## Homework Equations

PE = mgh

KE = 1/2mv^2

## The Attempt at a Solution

Find the PE of the pendulum. The height of it at 17 degrees: .43856 meters (about).

PE = 3.2*9.81*.43856 = 13.767 Joules. But the online checker says 2.1 Joules.

What am I doing wrong? Or, am I doing it right, the online thing is just wrong?

Thanks,

Jordan

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