ENGI 1313 Mechanics I

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## ENGI 1313 Mechanics I

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**ENGI 1313 Mechanics I**Lecture 31: Mid-Term Review**Overall Mid-Term Results**• Class Statistics (259) • Average • 67% • Standard deviation • 17% • Standard deviation between sections • 3% • Solution Posted**Term A/B Exam (Mon. Oct 22)**• Results are not Back • Student Numbers • 200600816 • 200641421 • 200641728 • 200643385 • 200714459 • 200737914 • 200749075**No Record of Mid-Term Exam**• Contact Me Immediately to Resolve • Student Numbers • 200643849 • 200626752 • 200402782 • 200565687 • 200672285**Problem 1**• Determine the components of the F force acting along the u and v axes. • Given: • 1 = 70 • 2 = 45 • 3 = 60 • F = 250N**Problem 1 (cont.)**• Problem Characteristics • Force vectors • No right rectangular coordinate system • Forces on specified axes • Solution Method • Parallelogram or triangle construction • Law of sines**Problem 1 (cont.)**• Force Triangle Fv F = 250 N 2 = 45 1 = 70 Fu**Problem 2**• The three cables are used to support the lamp of weight W. Determine the force developed in each cable for equilibrium. • Given: • a = 4 m • b = 4 m • c = 2 m • W = 600 N 4 m 2 m 4 m W = 600 N**Problem 2 (cont.)**• Problem Characteristics • Particle Equilibrium • Scalar or vector approach • Solution Method • Summation of Forces 4 m 2 m 4 m W = 600 N**Problem 2 (cont.)**• FBD and Unit Vectors FAD 4 m 2 m 4 m FAB FAC W = 600 N**Problem 2 (cont.)**• Equilibrium Equation • Three Equations FAD 4 m 2 m 4 m FAB FAC W = 600 N**Problem 3**• Force Fis applied to the handle of the wrench. Determine the angle between the tail of the force Fand the handle AB. • Given: • a = 0.30 m • b = 0.50 m • F = 80 N • 1 = 30 • 2 = 45 F = 80N 1 2 0.3 m 0.5 m**Problem 3 (cont.)**• Problem Characteristics • Vector projection • Solution Method • Dot product F = 80N 1 2 0.3 m 0.5 m**Problem 3 (cont.)**• Unit Vectors • Dot Product F = 80N 30 45 0.3 m 0.5 m**Problem 4**• The hood of the automobile is supported by the strut AB, which exerts a force F on the hood. Determine the moment of this force about the hinged axis y. • Given: • a = 0.60 m • b = 1.50 m • c = 0.25 m • d = 1.00 m • F = 100 N**Problem 4 (cont.)**• Problem Characteristics • Moment about aspecified axis • Solution Method • Triple scalar product**Problem 4 (cont.)**• Unit Vector • Moment about Y-axis