工程與科技 大學 2年以上以前 想請問一下，為什麼把球拋上去的加速度是負的g？(如果是用跟重力相反方向來解釋的話，那為什麼球掉下來的加速度也還是負的g) 拜託跟我解釋一下！謝謝🙏🏻 wicy AP osses a o the air. Fall apply falling Ball effects glected. v = 0 at highest point TWO becomes less positive Aloiteralsos 正 V降低 400. During ascent, a=-g, speed decreases, and velocity y IQU setle sebj vex V增加 a = -g, speed increases, and velocity becomes more negative $1-991² y = 0 do bszzol Boy Beall During ste descent, Houe esileh V 負 已解決 回答數: 1
工程與科技 大學 2年以上以前 半衰期的問題 Radium 233Ra has a half-life of about 3.8 days. (a) Given 1 88 gram, how much will still be present after 1 day? (b) After 1 year? 待回答 回答數: 0
工程與科技 大學 2年以上以前 正合方程式的問題（工數） 有點毫無頭緒😵💫 求解 Section 1.3 Problems 測試是否為正合 In each of Problems 1-5, test the differential equation for exactness. If it is exact in some region R of the plane, find a potential function and a general solution, perhaps implicitly defined, that is valid for that region. If it is not exact on any region, do not attempt a solution. 1. 2y² + yexy + (4xy + xexy + 2y)y' = 0 2. 4xy + 2x + (2x² + 3y²)y' = 0 3. 4xy + 2x²y + (2x² + 3y²)y' = 0 4.2 cos(x+y) - 2x sin(x + y) - 2x sin(x + y)y' = 0 tlsx9 ² +y+ (3y² + x)y' = 0 5. 待回答 回答數: 0
工程與科技 大學 約3年以前 小弟不才，有人會這兩大題嗎🥲 (1) 有一部 460V、20hp、60Hz、6極三相感應電動機滿載運轉,當滑差率+3%時,試求出: (a)馬達轉速、(b)轉子頻率、(c)定子旋轉磁場轉速、(d)氣隙磁場轉速、(e)轉子磁場轉速相 對於轉子轉速、(f)轉子磁場轉速相對於定子及(g)定子旋轉磁場相對於轉子磁場轉速。 (2) 有一部 208V、60Hz、20hp、4極三相感應電動機,其 IEEE 等效電路參數如下: R = 0.120; R2 = 0.10; X = Xi = 0.250; Xm = 10.02 當該感應電機旋轉損失為400W 且滑差率5%時,試求出: (a)馬達轉速、(b)馬達電流、(c)定子銅損、(d)氣隙功率、(e)轉子銅損、(f)軸功率、(g)機械轉 矩、(h)軸轉矩及(i)效率。 待回答 回答數: 0
工程與科技 大學 約3年以前 想問要怎麼判斷這種類型的題目？ 試題1 部分答對 得分 0.25/配分1.00 P標示試題 Figure (left) below shows a LC circuit, the top view of the electric and magnetic field inside the capacitor is shown on the right Figure at some time t. Which of the following statements are corrects for the directions of the electric and magnetic fields inside the inductor (top view) and the current at this moment in the circuit? (0) DE A. The magnitude of the current I is increasing at this moment OB. E-field is pointing into page OC. The magnitude of the current I is decreasing at this moment ✓ D. B-field is pointing out of page ✓ E. E-field is counter-clock-wise X OF. The current I is clock-wise OG. E-field is clock-wise ✓H. The current I is counter-clock-wise 尚未解決 回答數: 1
工程與科技 大學 約3年以前 求解🆘 2. 試求下列偏微分方程式之通解。 Du (a) -= e' cos x dx zu (b) 2² = 0 3. 試求下列偏微分方程式之特解。 du (a) - = ecos x,u(0, y) = y ax ou -= xe", u(0, y) = cos y, u(1, y) = 0 (b) 2x² 待回答 回答數: 0
工程與科技 大學 約3年以前 工程數學 2. 請以分離變數法解:G.E. âu âu = à ax I.C. u(x,0)=e²x 3. 請以分離變數法求偏微分方程式之通解: du du G.E. =0 0<x<a,0<y<b, 2x² 9² B.C. u(0, y) = 0 u(a, y) = 0 u(x,0) = f(x) u(x, b) = g(x) x>0,t>0 u=0 0 u = g(x) du d'u a²+ 8₁² u= f(x) u=0 a 待回答 回答數: 0
工程與科技 大學 約3年以前 大一線性代數 請問這題怎麼解 EX. S = { 1 + 3x+X* ²X², X+2*, -3 +67€ 23, 3+48-28 229 2-48= 3} is a subset of P3, Find a subset of 5 that forms a basis of Spanis). 尚未解決 回答數: 1
