Bicycle coasting up a Hill

[PhyzicsOfHockey]

Homework Statement

Coasting along at 7.10 m/s, a 60.0 kg bicyclist on a 7.60 kg bicycle encounters a small hill. If the speed of the bicyclist is 6.00 m/s at the top of the hill, how much work was done on the bicyclist and her bike?

Homework Equations

KEf-KEi=W
.5mvi^2-.5mvf^2
kg*m^2*s^-2
m=60kg+7.60kg
v=m/s

The Attempt at a Solution

I tried finding the loss in KE and having that be the work done. I get

.5mVf^2 -.5mVi^2
.5*67.6kg*36 - .5*67.6kg*50.41

I get -487 J and it tells me this is the wrong answer? What did I do wrong?

 

[berkeman]

Please write out the whole equations. Include the mass and the units.

 

[Saketh]

I tried finding the loss in KE and having that be the work done. I get

.5m(Vf-Vi)^2 and I get -487 J and it tells me this is the wrong answer? What did I do wrong?

Your final expression is incorrect mathematically.

 

[PhyzicsOfHockey]

I relized i posted that wrong but the answer comes out to -487 the right way but that's the wrong answer. I edited and wrote everything out.