Max Compression of Spring with Friction: Solve Now!

[kerrwilk]

A 1 kg puck slides at 20m/s along ice, then hits and compresses a spring with a constant of 35N/M. When it first hits the spring, the puck experiences a frictional force of 4.0 N opposing its motion. What is the maximum compression of the spring?

Homework Equations

KE=1/2mv^2

The Attempt at a Solution

I can do these problems without the friction element but am unsure about how friction affects the outcome. Any help would be appreciated.

 

[Delphi51]

Initial KE = energy of spring + work done against friction

 

[kerrwilk]

Thanks for your help Delphi51. Is this how I would solve the problem?

.5mv*2=.5kd*2+Fd
.5(1)(20)*2=.5(35)d*2+(4)d
200=17.5d*2+4d
0=17.5d*2+4d- 200
d= 3.3m (quadratic formula)

Thanks again.