1. King Fahd University of Petroleum & Minerals
Mechanical Engineering
Dynamics ME 201 BY
Dr. Meyassar N. Al-Haddad
Lecture # 12

2. Rectangular Coordinates

3. Normal and Tangential Coordinates For circular path and y = f (x) problems
Change in magnitude of velocity
Change in velocity’s direction

4. Free-Body Diagram = tan-1(dy/dx) n an q n Ff at t mg FN
Select the object
Establish n, t, b coordinate system
Set an always acts in the positive n direction
Assume at acts in the positive t
Set W = mg always acts in a vertical direction–downward
Set normal force FN along normal line
Set frictional force Ff opposite to t direction
= tan-1(dy/dx) n an q n Ff at FN t mg

5. Review
Example 13-6
Example 13-7
Example 13-8
Example 13-9

6. Problem 13.8
v = 65 ft/s
aA = ? NA=?
smooth slope
W = 150 lb

7. Problem 13.68
m = 30kg
T = ? At 0 degree

8. Problem 13-80
w =5 lb k =10 lb/ft
unstretched length of 3m, N & a = ?

10. Thank You