求解🙏🏻

挑戰一:某連隊等速直線前進,部隊全長 600m,傳令兵自隊尾等速跑到隊首遞交報告給連長後, 立刻以原速率跑回隊尾,此時整個連隊恰好前進了800m,則全程傳令兵移動的路徑長為?/boom # A popular web video shows a jet airplane, a car, and a motorcycle racing from rest along a runway. Initially the motorcycle takes the lead, but then the jet takes the lead, and finally the car blows past the motorcycle. Here let's focus on the car and motorcycle and assign some reasonable values to the motion. The motorcycle first takes the lead because its (constant) acceleration am 8.40 m/s² is greater than the car's (constant) acceleration ac 5.60 m/s², but it soon loses to the car because it reaches its greatest 58.8 m/s before the car reaches its greatest speed 106 m/s. How long does speed the car take to reach the motorcycle? 16.6

想問這幾題🙏（第2想問D）

2. 一個質點作直線運動,其a-1關係式為a=6-31,若x=0時x = 0、vg=18m/s,則下列敘 述何者正確? (A) 在第2秒時,質點開始反向運動 (C) 最大正向位移為6公尺 (E) 從第2秒後物體之加速度與速度恆反向。 (B)最大正向速度為24m/s (B)4到6秒間之平均加速度為-9m/s?Q= V V6-V4 6-4

請問為什麼這題加速度會等於兩倍速度➗時間啊？為什麼是兩倍的速度🙏🙏🥺🥺

4. 升降機以等速率4公尺/秒上升,機上一男孩垂直向上拋出一球,球相對於升降機之初速 為 1.96 公尺/秒,設球不會撞到天花板,則球掉回男孩手上需要多久的時間?(g = 9.8 公尺/秒?) Iv=4. plant Jg=9.84 V₂₂ U V球机 1.96 /个 V V a = ¥// 98=296 5.96 18 1065 0143 t = 5196 016 a= 2 Vo = 2x1.96 9.8 g = 0.95

請問詳解：又由力學能守恆可知…下面的算式是怎麼求得的？

(C)擺繩長度化,在任一點時:可 擺繩方向上的合力 = 向心力 > T繩 - mg cos0 = ma = m 又由力學能守恆可知 190 mgl(cos - cost) = 1 2 l mv 故T繩 = mg cos +2mg(cos-cost) = 3mg cos0 - 2mg cose, 當0=0°時(最低點),擺繩張力最大 Tmax=3mg-2mg cost, mg

想請問這四題

98. A baseball is hit straight up and is caught by the catcher 2.0 s later. The maximum height of the ball during this interval is: 4.9 m 2÷2=1 XA) B) C) D) E) 7.4 m 19.4 m 38.8 m 19.6 m 122. DA If the x component of a vector A, in the xy plane, is half as large as the magnitude of the vector, the tangent of the angle between the vector and the x axis is: A) √3 B) 1/2 C) √3/2 3/2 D) E) 3 142. Two vectors lie with their tails at the same point. When the angle between them is increased by 20° the magnitude of their vector product doubles. The original angle between them was about: A - B = |A|| B|cos O 2 L² cose = L² cos (0+20²) 2005 = cos@casso. sing sino A) 0 B) 18° C) 25° D) 45° E) 90° BA 158. Identical guns fire identical bullets horizontally at the same speed from the same height above level planes, one on the Earth and one on the Moon. Which of the following three statements is/are true? A) III only B) I and II only - 0-9 cose-adsint I. The horizontal distance traveled by the bullet is greater for the Moon. II. The flight time is less for the bullet on the Earth. III. The velocities of the bullets at impact are the same. I and III only II and III only 1.1 cos@=-035n9. tant = 1/3 C) D) E) I, II, III h-Vortat² xoxt-txt tu-Jite

求解 136、137

D) E) none of these =11 136. Two vectors have magnitudes of 10 and 15. The angle between them when they are drawn with their tails at the same point is 65°. The component of the longer vector along the line of the shorter is: A) 0 B) 4.2 C) 6.3 D) 9.1 E) 14 137. Let S = (1 m)2 + (2 m)j + (2 m) and T = (3 m)2 + (4 m)k. The angle between these two vectors is given by: A) cos ¹(14/15) B) cos ¹(11/225) cos ¹(104/225) cos ¹(11/15) cannot be found since S and 7 do not lie in the same plane 138. Two vectors lie with their tails at the same point. When the angle between them is increased by 20° their scalar product has the same magnitude but changes from positive to negative. The original angle between them was: A) 0

啥🥲

What is the moment of inertia I for a uniform ring of radius R and mass M about an axis (perpendicular to the plane of ring) at its rim? (A) 0.5 MR2; (B) MR²; (C) 1.5 MR²; (D) 2 MR²; (E) None.

［高二 牛一］ 請問這一題的D選項：雨傘的水滴那個不是會飛出去嗎？為什麼這個不會呢 謝謝

C/ (BS D3 下列有關慣性現象之敘述,哪些正確? 19 (Alt半球的長程大砲往正北方發射時,將命中其正北方的目標物 (B)北半球的 長程大砲欲射 中正北方的目標物時,應朝北偏西發射 (C)不計 空氣阻力,有一 等速飛行的飛機連續丟下一批彈,則雷達所掃描到飛機與 炸彈的影像,恰成 一直線 (D) 乾冰圓盤靜置於一靜止轉盤的邊緣,因兩者間無摩擦,故當轉盤開 始旋轉時,乾水盤沿切線飛出(E)馬戲世界內的騎師,在奔馳的馬背上躍起, 因慣性作用又會落回馬背 ea plane CE 9 Bomb. 多

物理力矩 題目:7b 書中的是答案是62.8Nm (逆時針) 我不太能算出來qwq

le Scu a square object as shown (Fid c). O is the centre of the object. Which force(s) produce(s) the largest moment Y z Fig C about O? 7 What is the moment of the force about o in each of the following cases? (a) 5N 350 5 cos 350 ( 2 ) 25 cm Tolot - 1.02 Nom Canticalck) *(b) 50 N 35° 30° 1.2 m *8 Objects P and Q are put on the two sides of a plank pivoted at O (Fig d). The plank remains horizontal. The distance between P and O is da the

想問（1）、（2）題~~ 功率

a out 設某汽船在水上行進時,阻力與船速成正比。當汽船引擎的輸出功率為6kW時,船以18 kmh時速行駛,則多利亞 以 (1)船速變為2 倍時,引擎功率變為k kW。 (2)若引擎功率减為」,船速變為中人 km/h)。 Pav² 1.497. (1) 2x18 18 plantw