Set the ball and the barrier about two feet apart on the table. Grasp both ends of the ruler. Push the ball using the center of the ruler so the ball rolls, hits the barrier, and rebounds from it. Describe the motion of the ball as it moves. Identify the forces exerted on the ball from the time the ruler touches it.

Asteel tube (k=50 w/mk) of inner and outer diameter di = 20mm and do=26mm, respectively, is used to transfer heat from hot gases flowing over the tube (h-hot = 200w/m2k) to cold water flowing through the tube (h-cold = 8000 w/m2k). what is the cold-side overall heat transfer coefficient uc? to enhance heat transfer 16 straight fins of rectangular profile are installed longitudinally along the outer surface of the tube. the fins are equally spaced around the circumference of the tube, each having a thickness of 2mm and a length of 15mm. what is the corresponding overall heat transfer coefficient uc? *solve for uc in both cases*