Find the acceleration vector in terms of ur and u x.
r = a(4 - cos x) and dx/dt = 6
v(t) = r' (t) = a(4 +sinx) + (4-cosx) (1)
ll v(t) ll = sqrt( a^2 + (4-cox)^2) = sqrt(a^2 + (16 - cos x)^4)
= 4sqrt( a^2 + (-cosx)^4)
a(t) = r " (t) = ????
ur = V dot a / ll v ll = ????
* I think I might be off??? Any assistance???