King Fahd University of Petroleum & Minerals Mechanical Engineering Dynamics ME 201 BY Dr. Meyassar N. Al-Haddad Lecture # 17

Work and Energy relation Initial K.E + Work Done = Final K.E

Problem h= ? Rest v B = 100 km/h  = minimum N = 4 mg = 39.24m N

Power and Efficiency Power is defined as the amount of work performed per unit of time. “rate of downing work” Mechanical Efficiency :

Problem m=50 kg From rest Constant acc. V=4m/s after 8 m P in =? Watt Neglect friction  =0.74

Conservation of Mechanical Energy For a system of Particles

Problem 14 W = 6 Ib From rest Smooth S = ? Datum

Example 14-9

Problem K A =300 N/m k B =200 N/m m=2 kg s=? Datum