An idealized schematic of an "electromagnetic rail gun", which is designed to fire prejectiles at speeds up to 10km/s. The projectile P sits between and in contact with two parallel rails along which it can slide. A generator G provides a current that flows up one rail, across the projectile, and back down the other rail. ┌───────────────────┐ →→│ i → │ ↑ └─────────┬─┬───────┘┬ ↑ │i │ v │ G │↓│P → │ w ↓ │ │ │ ↓ ┌─────────┴─┴───────┐┴ →→│ ← i │ └───────────────────┘ ├───────────────────┤ L (a) Lat w be the distance between the rails, r the radius of the rails (presumed circular), and i the current. Show that the force on the projectile is to the right and given approximately by 1 iiμ w+r F = ─ ── ㏑─── 2 π r (b) If the projectile starts from the left end of the rail at rest find the speed v at which it is expelled at the right. 我看不懂他r的描述到底是什麽 由於我是自修普物 可以的话麻烦回答详细一点... btw 我想知道如何"正确的"回答物理题目... 很多要按计算机的题目让数学系出身的我很痛苦... 想顺便请教一下各位前辈使用''使用计算机的诀窍'' 题目出自 Physics - Halliday‧Resnick‧Krane - fifth edition ---- p.770 --

※ 发信站: 批踢踢实业坊(ptt.cc) ◆ From: 59.116.5.250 那如果要求炮口的初速 是不是直接算 FL=动能 ?? ※ 编辑: PhysiAndMath 来自: 59.116.5.250 (08/25 20:24)