普物第二章老师有勾选8题例题，考试也是类似这种题目。 因为很多人没有买课本，应同学之要求把题目和答案打上来。 (答案照课本写，与实际计算结果可能有些误差) 题目01 A person is standing on a bathroom scale. Which of the following is not a force exerted on the scale：a contact force due to the floor, a contact force due to the person’s feet, the weight of the person, the weight of the scale？ 翻译： 一个人站在浴室磁砖上，哪个不是磁砖的外力： 地板造成的接触力、脚造成的接触力、人的重量、磁砖的重量 Ans： the weight of the person(人的重量) Sol： 人的重量是地球和人之间的万有引力造成的超距力，并无作用在地板瓷砖上。 题目17 A sailboat, tied to a mooring with a line, weights 820N.The mooring line pulls horizontally toward the west on the sailboat with a force of 110N. The sails are stowed away and the wind blows from the west. The boat is moored on a still lake - no water currents push on it. Draw a free-body diagram for the sailboat and indicate the magnitude of each forece. 翻译： 一艘停泊在岸边的小船重820NT，系船索用一个水平向西110牛顿的力量拉着船， 而帆则因西边吹来的风而有一推力，船是停泊在一个平静的湖面－没有水波施力 於船。画出作用於船上的力图并预测各个力量的大小。 Ans： ↑820N向上：湖水给船的正向力 110N向西：系船索的张力←船→110向东：风施给帆（船）的力 ↓820N向下：船和地球的万有引力 Sol： 如解答 题目29 A barge is hauled along a straight-line section of canal by two horses harnessed to tow ropes and walking along the tow paths on either side of the canal. Each horse pulls with a force of 560N at an angle of 15°with the centerline of the canal.Find the net force on the barge. 翻译： 一艘运河上的平底船被两匹沿着运河旁小径行进的马以直绳拖行着，两匹 马各以560牛顿、与运河中心线夹角15度的力量拖行着船，试找出船的合力。 Ans： 1k N foward Sol： 560N*2*cos15°=1081.83693 题目41 .A young south African girl has a mass of 40.0 kg. (a)What is her weight in newtons ? (b)If she came to the United States, what would her weight be in pounds as measured on an American scale? Assume g=9.80N/kg in both locations. 翻译： 有个南非的女孩质量为40公斤。 (a)女孩的重量是多少牛顿? (b)若她到了美国，换算成美国单位，那是多少磅重？假设两地的g=9.80N/kg Ans： (a)392(b)88.1 Sol： (a)40*9.8=392 (b)一公斤约等於2.20462磅，40*2.20462=88.18480 题目57 A horse is trotting along pulling a sleigh through the snow. To move the sleigh,of mass m, straight ahead at a constant speed, the horse must pull with a force of magnitude T. (a)What is the net force acting on the sleigh? (b)What is the coefficient of kinetic friction between the sleigh and the snow? 翻译： 一匹马拉着雪撬，为了使雪橇(质量为m)以等速移动，马必须施加张力T。 (a)雪橇所受合力？ (b)雪橇与雪之间动摩擦造成的摩擦系数为何？ Ans： (a)0(b)T/mg Sol： (a)等速，所以合力为0 (b)动摩擦力=马的拉力，T=mg*摩擦系数，移项可得 题目69 A pulley is attached to the ceiling. Spring scale A is attached to the wall and a rope runs horizontally from it and over the pulley. The same rope is then attached to spring scale B. On the other side of scale B hangs a 120-N weight . What are the readings of the two scales A and B? The weights of the scales are negligible. 翻译： 一个滑轮固定在天花板上。一个弹簧秤A一端连接墙壁一端连接绳子，绳子水平穿 过定滑轮後垂下，与弹簧秤B连接，而弹簧秤B另一端与一个120Nt的重物连接。两 弹簧秤的读数各为何?弹簧秤的重量可忽略。 Ans： 都是120N Sol： 直绳上各点张力皆相等 附图:墙－弹簧A－滑轮 ∣ 弹簧B ∣ 120N的重物 题目85 An airplane is cruising along in a horizontal level flight at a constant velocity, heading due west. (a)If the weight of the plane is 2.6×10000 N,what is the net force on the plane? (b)With what force does the air push upward on the plane? 翻译： 一架飞机以固定的速度朝向着正西方水平飞行。 (a)如果飞机重2.6×10000 N，那飞机的净力是多少？ (b)多少朝上的力施加在飞机机身上？ Ans： (a)0 (b)2.6×10000 N Sol： (a)等速移动，合力为0(b)水平移动，空气给予飞机的浮力=飞机的重量 题目97 A computer weighing 87 N rests on the horizontal surface of your desk. The coefficient of friction between the computer and the desk is 0.60. (a) Draw a free-body diagram for the computer. (b) What is the magnitude of the fricitional force acting on the computer? (c) How hard would you have to push on it to get it to start to slide across the desk? 翻译： 有一台重87牛顿的电脑水平的放在你的桌面上，电脑与桌面的共同摩擦系数为0.6。 (a)为你的电脑画一张自由体图(FBD) (b)作用於电脑上的摩擦力有多大 (c)你需要施多大的力才能使电脑移动 Ans： ↑桌子给电脑的正向力 (a)电脑 ↓电脑和地球的万有引力 (b)0 (c)52 N Sol： (a)如图 (b)水平方向无外力，所以净摩擦力等於0 (c)87 N *0.6=52.2 N 用完之後的感想一整个就是so sad，ptt不好编辑的说...... 影印店也不可能帮忙影印书本题目。一题一题输入word里面也很累的说， 所以......谁家里有高解析度的扫描机可以直接将题目扫描成文字档的， 这样可以省掉很多功夫和时间 ps.需要例题的word档的人在跟我要 --

※ 发信站: 批踢踢实业坊(ptt.cc) ◆ From: 59.126.51.177