Question

An 8.7 kg block slides with initials speed of 1.66 m/s across a level floor. How far does the block slide before it comes to rest!?

I used F= m(v(sq)/2s)...is that right?

Answer 1

No. You need the retarding force of friction.

Vf^2=vi^2 + 2ad and you are solving for d. But a=force/mass
and force=mu*mg