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## Homework Statement

I wasn't sure if i was doing this problem correctly, if anyone could double check for me, that would be great!

You ride your bicycle down a hill. Your total mass is 40 kg. At the top of the hill, your

speed is 5 m/s. The hill is 20 m high and 200 m long. If the force of friction is 20 N, what is

your speed at the bottom of the hill?

## Homework Equations

## The Attempt at a Solution

Top =

KE = 1/2 m v ^2

KE = 1/2 (40) (5)^2 = 500

PE = mgh

(40) (9.8) (20) = 7840

W = Fd

(20)(200)= 4000

7840 - 4000

=3840

3840 + 500 = 4340 = 1/2 (40) v ^2

divide both sides by 20

take the square root, and got 14.7 as my answer...