ME 311A – M8. ROLLING BODIES IN PURE CONTACT 2023-2024
M8. ROLLING BODIES IN PURE CONTACT
1. Cylinders Rolling in opposite direction:
A. Tangential speed
V1 = V2 = πD1N1 = πD2N2
B. Relation of diameter and speed
D1 N 1 = D2 N 2
C. Velocity Ratio
VR = Speed of Driver/Speed of Driven
VR = N1/N2 = D2/N1.
D. Center Distance = R1 + R2 = (D1 + D2)/2
2. Cylinders Rolling in the same direction
A. Tangential speed
V1 = V2 = πD1N1 = πD2N2
B. Relation of diameter and speed
D1 N 1 = D2 N 2
C. Velocity Ratio
VR = Speed of Driver/Speed of Driven
VR = N1/N2 = D2/N1.
D. Center Distance = R2 – R1 = (D2 – D1)/2
FORMATIVE ASSESSMENT
1. Two parallel shafts connected by pure rolling turn in
the same direction and having a speed ratio of 2.75.
What is the distance of the two shafts if the smaller
cylinder is 22 cm in diameter?
A. A. 16.60 cm
C. 30.25 cm
B. C. 25.25 cm
D. 19.25 cm
2. Three cylinders A:B:C has a speed ratio of 3:2:4 are
externally in contact side by side. If center distance
between cylinder A and C is 30 in, find the diameter of
cylinder B.
A. 15.34 in
C. 18.95 in
B. 12.34 in
D. 9.37 in
3. Two cylinders rolling in the opposite direction has a
speed ratio of 3. If the diameter of driver is 10 inches,
find the center distance between cylinders.
A. 15 in
C. 10 in
B. 25 in
D. 20 in
4. Two cylinders rolling in the same direction has a speed
ratio of 2.5 and center distance of 50 cm. Find the
diameters of the larger cylinder.
A. 56.34 in
C. 263/45 in
B. 166.67 in
D. 66.67 in
5. Four cylinders rolling in opposite directions has a speed
ratio of A:B:C:D = 5:3:1:4. If center distance between
cylinder A and C is 70 inches, find the diameter of
cylinder D.
A. 18.75 in
C. 26.34 in
B. 12.45 in
D. 16 .37 in
6. A pulley has a tangential velocity of 75 fpm. If pulley
diameter is 10 inches, find the speed of the speed.
A. 24.34 rpm
C. 28.65 rpm
B. 34.22 rpm
D. 32.34 rpm
7. Three cylinders A:B:C rolling in external contact has a
speed ratio of 4:2:1. If the diameter of cylinder A is 10
cm, find the center distance between cylinder A and C.
A. 35 cm
C. 55 cm
B. 45 cm
D. 60 cm
8. Shaft A with 12 inches diameter pulley running at 250
rpm is connected to shaft B by means of 26 inches
diameter pulley. Another pulley on shaft B 16 inches
diameter is connected to 10 inches diameter pulley on
shaft C. Find the speed of shaft C.
A. 184.61 rpm
C. 284.56 rpm
B. 173.45 rpm
D. 197.44 rpm