For the particle of Prob. 12.76, show (a) that the velocity of the particle and the centra...

For the particle of Prob. 12.76, show (a) that the velocity of the particle and the central force F are proportional to the distance r from the particle to the center of force O, (b) that the radius of curvature of the path is proportional to r 3.

Fig. P12.77