A particle shown in the original figure is just able to complete vertical circular motion.Find the ratio of its kinetic energy at point A to its kinetic energy at point B.

Question

G1 Physics · Accepted Answer

For a particle just able to complete the vertical circle, v² = 5gR at the lowest point. From the geometry in the source figure, K E A E_A E A ​ = 2mgR and K E B E_B E B ​ = mgR. Therefore, K E A / K E B E_A/KE_B E A ​ / K E B ​ = 2.