課程名稱︰靜力學 Statics 課程性質︰機械系大一必帶 課程教師︰施文彬 開課學院： 工學院 開給 工學院 開課系所︰ 機械系 開給 機械系 考試日期（年月日）︰2013.1.8 考試時限（分鐘）：2小時10分鐘(10:20~12:30) 是否需發放獎勵金：是 （如未明確表示，則不予發放） 試題 : Please provide details of your calculation. Good luck!! 1. (20%) A machine is shown as the picture. Rod BC is connected to the block C through a pin and passes through a collar welded to end B of lever AB. The block C is put on a platform that is supported by a screw. The screw is double-threaded and right-handed viewed from below. It has a pitch of 1.5 mm and a mean diameter of 8 mm. A couple of 30 N-m is applied to the lever as shown. The hinge and the pin are frictionless. Let the coefficient of static friction of all contacts is 0.25. The block C is about to move downward. (a) Draw the free body diagram of the lever AB. (b) Draw the free body diagram of the rod BC and Block C. (c) Determine Couple M that is required to hold the system in equilibrium. 第1題圖形：http://tinyurl.com/ahzxb8j 2. (20%) (a) Consider a flat belt passing over a fixed cylindrical drum. Please derive the relation between T and T 1 2 which can be applied to the problem involving a flat belt passing over the fixed cylindrical drum. ╭　　　　　　μβ ╮ │ T / T = e │ ╰ 2 1 ╯ (b) The simple band brake is constructed so that the ends of the friction belt are connected to the pin at A and the lower lever arm at B. If the drum is subjected to a torque of M = 120 N-m, determine the smallest force P applied to the lever that is required to hold the drum stationary.The coefficient of static friction between the belt and the drum is 0.5. The pin at O is frictionless. 第2題圖形： http://tinyurl.com/bxgykap http://tinyurl.com/b3hrxh8 3. (20%) (a) The cable AB carries a load uniformly distributed along the horizontal. Draw the F.B.D. of the CD section of the cable. 　　　　　　　　　　　2 ╭　　　　　　 w x ╮ │ Parabola: y = ─── │ ╰ 2 T ╯ 0 (c) A chain is fixed at its end and hoisted at its midpoint B using a crane. If the chain has weight of 0.3 kN/m along the horizontal, determine the minimum height h of the hook in order to Iift the chain completely off the ground. What is the horizontal force at pin A when the chain is in this position? 第3題圖形： http://tinyurl.com/aae5t87 http://tinyurl.com/a2jnofm 4. (20%) Neglect the weight of the mechanism and all frictions. (a) Apply the principle of virtual work to determine the ratio P/Q of the forccs that are required to maintain equilibrium of the mechanism for any arbitrary angle θ. (b) Determine the forces in member ABC in terms of Q， a and θ? 第4題 與 第5題 圖形： http://tinyurl.com/cwxxl5d 5. (20%) The simply supported truss is 15 m high and 16 m long. A 60 kN force is applied at E as shown. (a) Is there any zero-force member in the truss shown? If yes, please determine the zero-force members by analyzing a the F.B.D. If no, please explain the reasons? (b) Determine the forces in members AC, AD, and DE. (c) Determine the forces in members GI, FH, GH. --

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