Comet Halley moves about the Sun in an elliptical orbit with its closest approach to the Sun being about d1=0.59 AU and its greatest distance is d2=35.0 AU (1AU = 149,597,871 km). There are no net torques on the comet, including the torque resulting from gravity since it is a radial force. The comet's speed at its closest approach is 54 km/s. What is its speed when it is furthest away from the sun?