Law of conservation of enegry and one task

[p_kolya]

Law of conservation of enegry and one task :)

I must to do it, but I have no ideas about how to do...
------------
The washer hits on a horizontal surface of an ice under the corner a=60 and jumps aside under the corner b = 30. Factor of a sliding friction of the washer on the ice u = 0,04. Find losses of kinetic energy of the washer at impact. Movement of the washer consider forward.
------------
Thanks.

 

[H_man]

What are the units of a and b?

 

[p_kolya]

Degrees :)
Someone told me that dp = F * dt, where F is force of friction. Next write law of conservation momentum and energy. And next solve some equtions :)