A 8.63 kg box slides down a long, frictionless incline of angle 20 degrees. It starts from rest at time t = 0 at the top of the incline a height 24.6 m above ground.(adsbygoogle = window.adsbygoogle || []).push({});

Find the potential and kinetic energy of the box at t = 1.8s. Answer in units of J.

acceleration is gsin20

so I got velocity

by gsin20 x 1.8 seconds

and then I used .5mv^2 to find KE

and then for PE

I found PE at the highest point

which is mgh

and then subtracted KE from that

I got 1925.2569 J for PE and 157.3863974J for KE (ignore sig figs)

I entered this into UTexas and got it wrong.

Please help.

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# Homework Help: Energy Problem

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