※ [本文转录自 NTU-Exam 看板] 作者: jhs0909 (秉) 看板: NTU-Exam 标题: [试题] 94下 洪在明 普通物理学乙 期中考 时间: Fri Apr 21 16:32:50 2006 课程名称︰普通物理学乙 课程性质︰必修或选修可抵通识 课程教师︰洪在明 开课系所︰物治系 考试时间︰2006.4.21 14:20~17:20 试题 : (g = 10.0 m/s^2) 1. (Problem 2.31) A woodpecker's (啄木鸟) brain is specially protected from large decelerations by tendonlike (韧带) attachments inside the skull. While pecking on a tree the woodpecker's head comes to a stop from an initial velocity of 0.600 m/s in a distance of only 2.00 mm. (a) Find the decelerations in m/s^2 and in multiples of g. (b) Calculate the stopping time. 2. (Problem 2.44) A very srong, yet inept (不敏捷) , shot putter (铅球选手) puts the shot straight up with an initial velocity of 11.0 m/s. How long does he have to get out of the way if the shot was released at a height of 2.20m, and he is 1.80m tall? 3. (Problem 3.36) Gun sights are adjusted to aim high to compensate for the effect of gravity, effectively making the gun accurate only for a specific range. (a) If a gun is sighted to hit targets that are at the same height as the gun and 100m away, how low will the bullet hit if aimed directly at a target 150 m away? The muzzle (枪管) velocity of the bullet is 275 m/s. (b) Discuss qualitatively how air resistance will affect this problem. 4. (Example 4.8) Suppose a girl pulls on the leash of her beagle (10 kg) who refuses to go by lying down on its back. If the coefficient of static friction between his back and the ground is 0.700, how much force is required to get him moving when the leash (a) is horizontal, (b) makes an angle of 30度 to the ground? 5. (Problem 4.58) Consider a 50 kg mountain climber in the figure. (a) Find the tension in the rope and the force that the mountain climber must exert with her feet on the vertical rock face to remain stationary. Assume the force is exerted parallel to her legs. Also, assume negligible force exerted by her arms. (b) What is the minimum coefficient of friction between her shoes and the cliff? 6. (Problem 5.14) What force must be exerted by the wind to support a 2.50 kg chicken in the position shown in the figure? 7. (Problem 5.40) What force must the woman in the figure exert on the floor with each hand to do a push-up? Assume that she moves up at a constant speed. (b) The triceps muscle in the back of her upper arm has an effective lever arm of 1.5 cm, and she exerts force on the floor a horizontal distance of 20.0 cm from the elbow joint. Calculate the force in tricepts muscle, and its ratio to her weight. 8. (Problem 5.41) A father lifts his child as shown in the figure. What force must the upper leg muscle exert to lift the child at a constant speed? --

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