[問題] 熱力學－basic thermdynamics

看板Physics作者c22764942 (自由海豚)時間14年前 (2012/01/24 11:54)推噓1(1推 0噓 6→)

留言7則, 3人參與討論串1/1

各位新年好，小弟又來發問了， 1.What is the net force acting on a car cruising at a constant velocity of 70km/h (a) on a level road and (b) on an uphill road? 這淨力是等於動摩擦力嗎？我不太懂這題目的意思？ on a level road：阻力較小，所需要的淨力較小。 on an uphill road：阻力較大，為了維持等速，所需要的淨力較大。但是我該用哪個定律解釋？ 2.A 5-kg rock is thrown upward with a force of 150 N at a location where the local gravitational acceleration is 9.79 m/s2. Determine the acceleration of the rock, in m/s2. 這題我看了好幾次，都沒有很懂題目想要表達的意思，他所想求解的加速度 at rock F=ma => 150N=5*a => a=30m/s2 是這樣子嗎？ -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 125.227.223.110

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