physics
posted by Katie on .
A spherically symmetric object, with radius R = 0.50 m and mass M = 1.3 kg, rolls without slipping across a horizontal floor, with velocity V = 2.1 m/s. It then rolls up an incline with an angle of inclination θ = 25° and comes to rest a distance d = 3.0 m up the incline, before reversing direction and rolling back down. Find the moment of inertia of this object about an axis through its center of mass.
PLEASE HELP ASAP!!!!
Due in an hour and a half.
I was able to follow other work but when I take 3sin(25) I get a negative number and that screws up the whole answer because you can't take the square root of a negative.

KE=PE
KE = mv^2/2 + Iω^2/2 =
=mv^2/2 +Iv^2/2R^2
PE= mgh = mgdsinα
I= 2r^2(mgdsinα mv^2/2)/v^2