FIGURE 10-3
-Fig. 10-3 illustrates a simplified roller bearing. The outer hollow cylinder has a radius of 1.20 cm and is stationary. The inner cylinder has a radius of 1.00 cm and is rotating at 9.00 rpm. Between the two cylinders are several small cylinders with a radius of 0.100 cm, which roll without slipping on both the inner and outer cylinders. Only one of these cylinders is shown in the figure. How long does it take a small cylinder to complete a full revolution around the inner cylinder?
A)6.00 s
B)14.7 s
C)5.64 s
D)0.542 s
E)1.38 s

Question

FIGURE 10-3 
-Fig. 10-3 illustrates a simplified roller bearing. The outer hollow cylinder has a radius of 1.20 cm and is stationary. The inner cylinder has a radius of 1.00 cm and is rotating at 9.00 rpm. Between the two cylinders are several small cylinders with a radius of 0.100 cm, which roll without slipping on both the inner and outer cylinders. Only one of these cylinders is shown in the figure. How long does it take a small cylinder to complete a full revolution around the inner cylinder?
A)6.00 s 
B)14.7 s 
C)5.64 s 
D)0.542 s 
E)1.38 s

Quizplus · Accepted Answer

The small cylinder completes a full revolution around the inner cylinder in the time it takes the inner cylinder to rotate once. The inner cylinder rotates at 9.00 rpm, which means it takes 60/9 = 6.67 seconds for one full rotation. However, the small cylinder also rolls on the inner cylinder, effectively doubling the distance it travels, so it takes 6.67 * 2 = 13.34 seconds, which is approximately 14.7 seconds.

FIGURE 10-3 -Fig. 10-3 Illustrates a Simplified Roller Bearing. the Outer Hollow