MCP๋กœ ์—ฐ๊ฒฐ โ†’

๊ณ„์‚ฐ ์ž…๋ ฅ

๊ณต์‹

๊ด‘๊ณ 

๊ฒฐ๊ณผ

์ตœ๊ณ  ๋†’์ด
34.42
๋ฏธํ„ฐ
๋น„ํ–‰ ์‹œ๊ฐ„
5.299 s
์ตœ๋Œ€ ์‚ฌ๊ฑฐ๋ฆฌ
79.48 m
vx / vy
15 / 25.98 m/s
์‹œ๊ฐ„ t (์ดˆ) ๊ฑฐ๋ฆฌ l (m) ๋†’์ด h (m) ์†๋„ (m/s)
0 0 0 30
0.1 1.5 2.549 29.155
0.2 3 5 28.318
0.3 4.5 7.353 27.492
0.4 6 9.608 26.675
0.5 7.5 11.765 25.87
0.6 9 13.823 25.077
0.7 10.5 15.784 24.299
0.8 12 17.646 23.535
0.9 13.5 19.411 22.788
1 15 21.077 22.059
1.1 16.5 22.646 21.35
1.2 18 24.116 20.664
1.3 19.5 25.488 20.002
1.4 21 26.763 19.367
1.5 22.5 27.939 18.762
1.6 24 29.017 18.19
1.7 25.5 29.997 17.654
1.8 27 30.879 17.157
1.9 28.5 31.662 16.703
2 30 32.348 16.296
2.1 31.5 32.936 15.938
2.2 33 33.426 15.634
2.3 34.5 33.817 15.386
2.4 36 34.111 15.198
2.5 37.5 34.306 15.071
2.6 39 34.404 15.008
2.7 40.5 34.403 15.008
2.8 42 34.304 15.073
2.9 43.5 34.107 15.2
3 45 33.812 15.389
3.1 46.5 33.419 15.638
3.2 48 32.928 15.943
3.3 49.5 32.339 16.301
3.4 51 31.652 16.709
3.5 52.5 30.867 17.164
3.6 54 29.984 17.661
3.7 55.5 29.002 18.198
3.8 57 27.923 18.771
3.9 58.5 26.745 19.376
4 60 25.47 20.011
4.1 61.5 24.096 20.673
4.2 63 22.625 21.36
4.3 64.5 21.055 22.069
4.4 66 19.387 22.798
4.5 67.5 17.621 23.546
4.6 69 15.757 24.309
4.7 70.5 13.795 25.088
4.8 72 11.735 25.881
4.9 73.5 9.577 26.686
5 75 7.321 27.503
5.1 76.5 4.966 28.33
5.2 78 2.514 29.167
5.3 79.5 -0.036 30.012
5.4 81 -2.685 30.865
5.5 82.5 -5.431 31.726
5.6 84 -8.276 32.593
5.7 85.5 -11.219 33.467
5.8 87 -14.259 34.346
5.9 88.5 -17.398 35.231

์ด ๊ณ„์‚ฐ๊ธฐ๋กœ ํ•  ์ˆ˜ ์žˆ๋Š” ์ผ

์ด ๋„๊ตฌ๋Š” ์ด์ƒ์ ์ธ ํฌ๋ฌผ์„  ์šด๋™์„ ๋ชจํ˜•ํ™”ํ•ฉ๋‹ˆ๋‹ค. ์ง€๋ฉด์—์„œ ์ฃผ์–ด์ง„ ์ดˆ๊ธฐ ์†๋„์™€ ๊ฐ๋„๋กœ ๋ฐœ์‚ฌ๋œ ๋ฌผ์ฒด๊ฐ€ ์ผ์ •ํ•œ ์ค‘๋ ฅ๋งŒ ๋ฐ›๊ณ  ๊ณต๊ธฐ ์ €ํ•ญ ์—†์ด ์›€์ง์ด๋Š” ์ƒํ™ฉ์ด์ฃ . ์‹œ๊ฐ„์˜ ํ๋ฆ„(๋˜๋Š” ์ˆ˜ํ‰ ๊ฑฐ๋ฆฌ์˜ ๋ณ€ํ™”)์— ๋”ฐ๋ผ ๊ถค์ , ์ฆ‰ ๋†’์ด์™€ ์ˆ˜ํ‰ ๊ฑฐ๋ฆฌ๋ฅผ ํ‘œ๋กœ ์ •๋ฆฌํ•˜๊ณ , ํ•ต์‹ฌ ์ˆ˜์น˜์ธ ๋น„ํ–‰ ์‹œ๊ฐ„, ์ตœ๊ณ  ๋†’์ด, ์ตœ๋Œ€ ์‚ฌ๊ฑฐ๋ฆฌ๋ฅผ ํ•จ๊ป˜ ๋ณด์—ฌ์ค๋‹ˆ๋‹ค. ์—ฌ๊ธฐ์— ์ ์šฉ๋˜๋Š” ๋ฌผ๋ฆฌ๋Š” ์–ด๋””์„œ๋‚˜ ๋™์ผํ•œ ๋‰ดํ„ด ์—ญํ•™์ด๋ฏ€๋กœ, ๋‚˜๋ผ์™€ ๊ด€๊ณ„์—†์ด ๋˜‘๊ฐ™์ด ์„ฑ๋ฆฝํ•ฉ๋‹ˆ๋‹ค.

์‚ฌ์šฉ ๋ฐฉ๋ฒ•

์ดˆ๊ธฐ ์†๋„ \(v\)๋ฅผ ์ž…๋ ฅํ•˜๊ณ  ๋‹จ์œ„(m/s ๋˜๋Š” km/h)๋ฅผ ์„ ํƒํ•˜์„ธ์š”. ๋ฐœ์‚ฌ๊ฐ \(\theta\)๋Š” ๋„(ยฐ) ๋‹จ์œ„๋กœ 0~90 ์‚ฌ์ด์—์„œ ์ง€์ •ํ•˜๊ณ , ์ค‘๋ ฅ ๊ฐ€์†๋„ \(g\)๋Š” ์ง€๊ตฌ ํ‘œ์ค€ ์ค‘๋ ฅ ๊ธฐ์ค€ ๊ธฐ๋ณธ๊ฐ’ 9.80665 m/sยฒ๋ฅผ ์‚ฌ์šฉํ•ฉ๋‹ˆ๋‹ค. ๋‹ค์Œ์œผ๋กœ ๋ณ€ํ™”์‹œํ‚ฌ ๊ธฐ์ค€ ๋ณ€์ˆ˜๋ฅผ ๊ณ ๋ฆ…๋‹ˆ๋‹ค. ์‹œ๊ฐ„์„ ์„ ํƒํ•˜๋ฉด \(t = \text{์‹œ์ž‘๊ฐ’} + n \times \text{์ฆ๊ฐ€๋Ÿ‰}\) ํ˜•ํƒœ๋กœ ํ–‰์ด ์ƒ์„ฑ๋˜๊ณ , ๊ฑฐ๋ฆฌ๋ฅผ ์„ ํƒํ•˜๋ฉด \(l = \text{์‹œ์ž‘๊ฐ’} + n \times \text{์ฆ๊ฐ€๋Ÿ‰}\) ํ˜•ํƒœ๋กœ ํ–‰์ด ์ƒ์„ฑ๋˜์–ด ๊ฐ ๊ฑฐ๋ฆฌ์—์„œ์˜ ์‹œ๊ฐ„๊ณผ ๋†’์ด๋ฅผ ๊ตฌํ•ฉ๋‹ˆ๋‹ค. ์‹œ์ž‘๊ฐ’, ์ฆ๊ฐ€๋Ÿ‰, ๋ฐ˜๋ณต ํšŸ์ˆ˜๋ฅผ ์กฐ์ •ํ•ด ํ‘œ์˜ ์„ธ๋ฐ€ํ•จ์„ ์กฐ์ ˆํ•  ์ˆ˜ ์žˆ์Šต๋‹ˆ๋‹ค.

๊ณต์‹ ํ’€์ด

๋ฐœ์‚ฌ ์†๋„๋Š” ์ˆ˜ํ‰ ์„ฑ๋ถ„ \(v_x = v\cdot\cos\theta\)์™€ ์ˆ˜์ง ์„ฑ๋ถ„ \(v_y = v\cdot\sin\theta\)๋กœ ๋‚˜๋‰ฉ๋‹ˆ๋‹ค. ์ˆ˜ํ‰ ์šด๋™์€ ๋“ฑ์† ์šด๋™์ด๋ผ \(l(t) = v_x\cdot t\)์ด๊ณ , ์ˆ˜์ง ์šด๋™์€ ์ผ์ •ํ•˜๊ฒŒ ๊ฐ์†ํ•˜๋ฏ€๋กœ \(h(t) = v_y\cdot t - \tfrac{1}{2}g\cdot t^2\)์ž…๋‹ˆ๋‹ค. ์‹œ๊ฐ„์„ ์†Œ๊ฑฐํ•˜๋ฉด ํฌ๋ฌผ์„  ์‹ $$h(l) = l\cdot\tan\theta - \frac{g\cdot l^2}{2v^2\cos^2\theta}$$ ์„ ์–ป์Šต๋‹ˆ๋‹ค. ํฌ๋ฌผ์ฒด๋Š” \(T = 2v\cdot\sin\theta/g\) ํ›„์— ๋ฐœ์‚ฌ ๋†’์ด๋กœ ๋˜๋Œ์•„์˜ค๊ณ , \(H = v^2\sin^2\theta/(2g)\)์—์„œ ์ตœ๊ณ ์ ์— ๋„๋‹ฌํ•˜๋ฉฐ, \(R = v^2\sin(2\theta)/g\) ๋งŒํผ ๋–จ์–ด์ง„ ์ง€์ ์— ์ฐฉ์ง€ํ•ฉ๋‹ˆ๋‹ค.

๋ฐœ์‚ฌ ์‹œ ์ˆ˜ํ‰ยท์ˆ˜์ง ์„ฑ๋ถ„์œผ๋กœ ๋ถ„ํ•ด๋œ ์†๋„ ๋ฒกํ„ฐ
๋ฐœ์‚ฌ ์†๋„ \(v\)๋ฅผ ์ˆ˜ํ‰ ์„ฑ๋ถ„(\(v\cos\theta\))๊ณผ ์ˆ˜์ง ์„ฑ๋ถ„(\(v\sin\theta\))์œผ๋กœ ๋ถ„ํ•ด.
๋ฐœ์‚ฌ๊ฐ, ์†๋„ ์„ฑ๋ถ„, ์ตœ๊ณ  ๋†’์ด, ๋„๋‹ฌ ๊ฑฐ๋ฆฌ๊ฐ€ ํ‘œ์‹œ๋œ ํฌ๋ฌผ์„  ๊ถค์ 
๋ฐœ์‚ฌ๊ฐ \(\theta\), ์ดˆ๊ธฐ ์†๋„ \(v\), ์ตœ๊ณ  ๋†’์ด, ์ด ๋„๋‹ฌ ๊ฑฐ๋ฆฌ๋ฅผ ๋‚˜ํƒ€๋‚ธ ํฌ๋ฌผ์„  ์šด๋™ ๊ถค์ .

์˜ˆ์ œ ํ’€์ด

\(v = 30\) m/s, \(\theta = 60\degree\), \(g = 9.80665\) m/sยฒ์ธ ๊ฒฝ์šฐ: \(v_x = 15\) m/s, \(v_y = 25.98\) m/s์ž…๋‹ˆ๋‹ค. \(t = 0.1\)์ดˆ์ผ ๋•Œ ๋ฌผ์ฒด๋Š” \(l = 1.5\) m, \(h = 2.549\) m ์œ„์น˜์— ์žˆ์Šต๋‹ˆ๋‹ค. ๋น„ํ–‰ ์‹œ๊ฐ„์€ $$T = 2\times 25.98/9.80665 = 5.299 \text{ ์ดˆ},$$ ์ตœ๊ณ  ๋†’์ด๋Š” $$H = 25.98^2/(2\times 9.80665) = 34.41 \text{ m},$$ ์ตœ๋Œ€ ์‚ฌ๊ฑฐ๋ฆฌ๋Š” $$R = 900\times\sin(120\degree)/9.80665 = 79.48 \text{ m}$$ ์ž…๋‹ˆ๋‹ค.

์ž์ฃผ ๋ฌป๋Š” ์งˆ๋ฌธ

๊ณต๊ธฐ ์ €ํ•ญ์„ ๋ฐ˜์˜ํ•˜๋‚˜์š”? ์•„๋‹ˆ์š”. ์ง„๊ณต(๊ณต๊ธฐ ์ €ํ•ญ ์—†์Œ) ์ƒํƒœ์˜ ํฌ๋ฌผ์ฒด๋ฅผ ๊ฐ€์ •ํ•˜๋ฏ€๋กœ, ์‹ค์ œ ์‚ฌ๊ฑฐ๋ฆฌ๋Š” ๋ณดํ†ต ์ด๋ณด๋‹ค ์งง์Šต๋‹ˆ๋‹ค.

\(\theta = 90\degree\)์ผ ๋•Œ๋Š” ์–ด๋–ป๊ฒŒ ๋˜๋‚˜์š”? ๋ฌผ์ฒด๊ฐ€ ์ˆ˜์ง์œผ๋กœ ๊ณง์žฅ ์˜ฌ๋ผ๊ฐ‘๋‹ˆ๋‹ค. \(v_x = 0\)์ด๋ผ ์ˆ˜ํ‰ ๊ฑฐ๋ฆฌ๋Š” 0์œผ๋กœ ์œ ์ง€๋ฉ๋‹ˆ๋‹ค. ๊ฑฐ๋ฆฌ ๊ธฐ์ค€ ๋ชจ๋“œ์—์„œ๋Š” 0์ด ์•„๋‹Œ ๊ฑฐ๋ฆฌ์— ๊ฒฐ์ฝ” ๋„๋‹ฌํ•˜์ง€ ๋ชปํ•˜๋ฏ€๋กœ ๋†’์ด๊ฐ€ ๋ชจ๋‘ 0์œผ๋กœ ํ‘œ์‹œ๋ฉ๋‹ˆ๋‹ค.

์ผ๋ถ€ ๋†’์ด๊ฐ€ ์Œ์ˆ˜๋กœ ๋‚˜์˜ค๋Š” ์ด์œ ๋Š” ๋ฌด์—‡์ธ๊ฐ€์š”? ๋น„ํ–‰ ์‹œ๊ฐ„์ด ์ง€๋‚œ ๋’ค์—๋Š” ํฌ๋ฌผ์ฒด๊ฐ€ ๋ฐœ์‚ฌ ๋†’์ด๋ณด๋‹ค ์•„๋ž˜๋กœ ๋–จ์–ด์ง€๊ธฐ ๋•Œ๋ฌธ์ž…๋‹ˆ๋‹ค. ํ‘œ๋Š” ๋ฌผ์ฒด๊ฐ€ ๊ณ„์† ๋‚ด๋ ค๊ฐ€๋Š” ๋™์•ˆ์˜ ๊ฐ’๋„ ๊ทธ๋Œ€๋กœ ๋‚˜์—ดํ•ฉ๋‹ˆ๋‹ค.

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