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<´ÙÀ½ ¾îÈÖ¸¦ Ȱ¿ëÇÏ¿© ºóÄÀ» ä¿öº¸¼¼¿ä> ( a force of attraction, As a result, in balance, gravity ) The moon is always moving. ´ÞÀº ¾ðÁ¦³ª À̵¿ÇÏÁö¿ä. In fact, the moon travels in space at about 3,700 kilometers per hour. ½ÇÁ¦·Î ´ÞÀº ÇÑ ½Ã°£¿¡ 3,700ų·Î¹ÌÅ͸¦ ¿òÁ÷ÀÔ´Ï´Ù. Then why is the moon still orbiting Earth and not traveling off into space? ±×·¯¸é ¿Ö ´ÞÀº Ç×»ó Áö±¸ÀÇ µÑ·¹¸¦ ¹þ¾î³ªÁö ¾Ê°í µµ´Â °ÍÀϱî¿ä? The answer has to do with Earth¡¯s gravity. ÇØ´äÀº Áö±¸ÀÇ Á߷°ú ¿¬°üÀÌ ÀÖ´ä´Ï´Ù. Gravity is (1)__________________________. Áß·ÂÀ̶õ ²ø¾î´ç±â´Â ÈûÀ» ¸»ÇÕ´Ï´Ù. Earth¡¯s gravity pulls on the moon. Áö±¸ÀÇ Áß·ÂÀº ´ÞÀ» ²ø¾î´ç±é´Ï´Ù. Earth¡¯s gravity keeps the moon from flying off into space. Áö±¸ÀÇ Áß·ÂÀº ´ÞÀÌ ¿ìÁÖ°ø°£À¸·Î ³¯¾Æ°¡´Â °ÍÀ» ¸·¾ÆÁÝ´Ï´Ù. The pull of Earth¡¯s (2)____________ balances the speed of the moon¡¯s motion. Áö±¸ÀÇ Áß·ÂÀÇ ²ø¾î´ç±èÀÌ ´ÞÀÇ À̵¿¼Óµµ°¡ ±ÕÇüÀ» ÀÌ·ç°Ô ÇÕ´Ï´Ù. (3)__________________, the moon remains in orbit around Earth. °á°úÀûÀ¸·Î ´ÞÀº Áö±¸ÀÇ ±Ëµµ¿¡ ¸Ó¹«¸£°Ô µÇ´Â °ÍÀÔ´Ï´Ù. Think of it this way. ÀÌ·± ½ÄÀ¸·Î »ý°¢ÇØ º¸¼¼¿ä. Imagine that you have a ball tied to a string. ²öÀ¸·Î ¸Ç °øÀÌ ÀÖ´Ù°í »ý°¢Çغ¸¼¼¿ä. Hold onto the end of the string. °øÀÇ ³¡À» ºÙÀâ°í ÀÖ¾î¿ä. Start spinning the ball around your head. ¸Ó¸® ÁÖÀ§·Î °øÀ» µ¹¸®±â ½ÃÀÛÇØº¸¼¼¿ä. The ball will orbit your head. °øÀº ¿©·¯ºÐÀÇ ¸Ó¸® ÁÖÀ§¸¦ ȸÀüÇϰÚÁö¿ä. The string acts like gravity to keep the ball from flying away. ²öÀº °øÀÌ ³¯¾Æ°¡Áö ¸øÇϵµ·Ï ¸¶Ä¡ Áß·Âó·³ ÀÛ¿ëÀ» ÇÏ´Â °ÍÀÌÁÒ. Now imagine that you cut the string while you are spinning the ball. ÀÚ ÀÌÁ¨ °øÀ» µ¹¸®°í ÀÖ´Â Áß¿¡ ²öÀ» Àß¶ó³½´Ù°í »ó»óÇØº¸¼¼¿ä. The ball¡¯s motion will send it flying away. °øÀº ¸Ö¸® ³¯¾Æ°¡ ¹ö¸®°ÚÁö¿ä. If there were no gravity, the moon would do the same thing. Áß·ÂÀÌ ¾ø´Ù¸é ´Þµµ ÀÌ¿Í °°´ä´Ï´Ù.. But gravity and the motion of the moon are (4)______________, so the moon continues to orbit Earth. ±×·¯³ª Á߷°ú ´ÞÀÇ ¿òÁ÷ÀÓÀº ±ÕÇüÀ» ÀÌ·ç°í ÀÖ´ä´Ï´Ù. ±×·¡¼ ´ÞÀº Áö¼ÓÀûÀ¸·Î Áö±¸ÀÇ µÑ·¹¸¦ µ¹°Ô µÇ´Â °ÍÀÌÁÒ. Answers (1) a force of attraction (2) gravity (3) As a result (4) in balance |
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