This is a fairly simple problem which i believe i know the answer to but the answer doesn't agree with the book i got it from.(adsbygoogle = window.adsbygoogle || []).push({});

Theres a 750 gram cart traveling 4 m/s, 2 meters later its traveling at 3 m/s. Calculate the average retarding force assuming only air resistance.

Here what I did:

KE= (1/2)*m*v^2 so deltaKE=(.5)*(.750)*(4^2-3^2)= 2.625

The Work=f*d. Since the Change in Kinetic Energy equals the work done on the object i did:

2.625=f*2. Hence f=(2.625/2)=1.3125 N.

I think thats right but is there something i might be possibly missing?

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# Homework Help: Basic Mechanics

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