课程名称︰普通物理甲上 课程性质︰必修 课程教师︰苏德润 开课学院：工学院 开课系所：化工系 考试日期（年月日）︰ 考试时限（分钟）：110分钟 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : 1.the ballistic pendulum was used to measure the speeds of bullets before electronic timing devices were developed.the version shown in Fig 1. consists of a large block of wood of mass M=5,4kg,hanging from two long cords. a bullet of mass m=9.5g is fired into the block,coming quickly to rest.the block+bullet then swing upward, their ce nter of mass rising a vertical distance h=6.3cm before the pendulum comes momentarily to rest at the end of its arc.what is the speed of the bullet just prior to the collision? 附图 http://ppt.cc/XJ~B 2.a uniform rope of mass m and length L hangs from a ceiling(a)show that the speed of a transverse wave on the rope is a function of y,the distance from the lower end,and is given by v^2=gy.(b)show that the time a transverse wave takes to travel the length of the rope is given by t=2√(L/g) 3.(a)in Fig-2,two identical springs of spring constant 7580N/m are attached to a block of mass 0.270 kg. what is the frequency of oscillation on the frictionless floor? (b)in Fig-2,two springs are attached to a block that can oscillate over a frictionless floor.if the left spring is removed,the block oscillates at a frequency of 30Hz.If instead, the spring on the right is removed,the block oscillates at a frequency of 50Hz.at what frequency does the block oscillate with both springs attached? 附图 http://ppt.cc/yHUn 4.a 0.485kg sample of liquid water and a sample of ice are placed in a thermally insulated container.the container also contains a device that transfers energy as heat from the liquid water to the ice at a constant rate P until thermal equilibrium is reached.the temperatures I of the liquid water and the ice are given in Fig-3 as functions of time t,the horizontal scale is set by ts=80.0min(a)what is rate P? (b)what is the initial mass of the ice in the container? (c)when thermal equilibrium is reached,what is the mass of the ice produced in this process? 附图 http://ppt.cc/uT7L -- I am Captain America~~~~ --

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