The free-rolling ramp has a weight { W }_{ r } . The crate, whose weight is { W }_{ c } , slides a distance d from rest at A, down the ramp to B. Determine the ramp’s speed when the crate reaches B. Assume that the ramp is smooth, and neglect the mass of the wheels. Given: { W }_{ r } = 120 lb , a = 3 , b = 4 , { W }_{ c } = 80 lb , d = 15 ft , g = { 32.2ft/s }^{ 2 }