A 30 g ball rolls around a 40-cm-diameter L-shaped track, shown in Figure 47, at 60 rpm. Rolling friction can be neglected. a. How many different contact forces does the track exert on the ball? Name them. b. What is the magnitude of the net force on the ball? FIGURE 47

Solution Step 1 of 3 a. How many different contact forces does the track exert on the ball Name them. When the ball is moving in the L shaped track as in the figure. If we neglect the rolling friction. Two forces will be acting on the ball, one being the normal force which is acting perpendicular to the contact surface. Another is the centripetal force which is acting inwards with respect to the circular path. Step 2 of 3 b. What is the magnitude of the net force on the ball Given data, Mass of the ball, m=30 g Using 1g = 10 kg3 m=30× 10 kg3 Radius of the L-shaped track,r = (diameter/2)=(40 cm/2)= 20cm Using 1 cm = 10 m2 r== 20× 10 m= 0.2 m Angular velocity, =60 rpm=60 rev/min Using 1min = 60 sec 1 rev = 2 rad = 60 rev/min( 21 rev)( 60 sec) = 6.28 rad/sec