ÌâÄ¿ÄÚÈÝ
20£®£¨1£©ÇóÒÒ³µ¼õËÙÔ˶¯µÄ¼ÓËÙ¶È´óСÖÁÉÙӦΪ¶à´ó£¿
£¨2£©Çó±û³µ¼õËÙÔ˶¯µÄ¼ÓËÙ¶È´óСÖÁÉÙӦΪ¶à´ó£¿
·ÖÎö £¨1£©µ±ÒÒ³µ×·Éϼ׳µËÙ¶ÈÇ¡ºÃÏàµÈʱ£¬ÒÒ³µÉ²³µÊ±¼ÓËÙ¶ÈΪ×îСֵ£®ÔÙ¸ù¾ÝÎ»ÒÆ¹ØÏµÇó½âʱ¼ä£¬¸ù¾ÝËÙ¶ÈÏàµÈÌõ¼þÇó³ö¼ÓËÙ¶È£®
£¨2£©ÒªÊ¹±û³µ²»×·ÉÏÒÒ³µ£¬ÁÙ½çÇé¿öÒ²ÊÇËÙ¶ÈÏàµÈʱÁ½³µ¾àÀëΪÁ㣬¸ù¾ÝËÙ¶Èʱ¼ä¹ØÏµ¹«Ê½ºÍÎ»ÒÆÊ±¼ä¹ØÏµ¹«Ê½ÁÐʽÇó½â±û³µµÄ×îС¼ÓËÙ¶È£®
½â´ð ½â£º£¨1£©¼×³µÉ²³µÊ±¼äΪ£º${t}_{¼×}^{\;}=\frac{{v}_{¼×}^{\;}-0}{{a}_{¼×}^{\;}}=\frac{5-0}{1}s=5s$¡¢Ù
µ±ÒÒ³µÓë¼×³µËÙ¶ÈÏàµÈʱ£¬ËٶȹØÏµÎª£º${v}_{ÒÒ}^{\;}={v}_{¼×}^{\;}$¡¢Ú
$8-{a}_{ÒÒ}^{\;}{t}_{1}^{\;}=5-{t}_{1}^{\;}$¡¢Û
Î»ÒÆ¹ØÏµÎª£º${x}_{ÒÒ}^{\;}={x}_{¼×}^{\;}+6m$£º$8{t}_{1}^{\;}-\frac{1}{2}{a}_{ÒÒ}^{\;}{t}_{1}^{2}=5{t}_{1}^{\;}-\frac{1}{2}{t}_{1}^{2}+6$¡¢Ü
ÁªÁ¢¢Û¢Ü??Á½Ê½¿ÉµÃ£º${a}_{ÒÒ}^{\;}=1.75m/{s}_{\;}^{2}$£®ÇÒ${t}_{1}^{\;}=4s£¼{t}_{¼×}^{\;}=5s$£¬¹Ê³ÉÁ¢£®
£¨2£©ÒÒ³µÉ²³µÊ±¼äΪ${t}_{ÒÒ}^{\;}=\frac{{v}_{ÒÒ}^{\;}-0}{{a}_{ÒÒ}^{\;}}=4.57s$µ±±û³µÓëÒÒ³µËÙ¶ÈÏàµÈʱ£¬
ËٶȹØÏµ${v}_{±û}^{\;}={v}_{ÒÒ}^{\;}$£º$10-{a}_{±û}^{\;}{t}_{2}^{\;}=8-1.75{t}_{2}^{\;}$¡¢Ý
Î»ÒÆ¹ØÏµ${x}_{±û}^{\;}={x}_{ÒÒ}^{\;}+6m$£º$10{t}_{2}^{\;}-\frac{1}{2}{a}_{±û}^{\;}{t}_{2}^{2}=8{t}_{2}^{\;}-\frac{1}{2}¡Á1.75{t}_{2}^{2}+6$ ¢Þ
ÁªÁ¢?¢ÜÁ½Ê½¿ÉµÃ£º${t}_{2}^{\;}=6s£¾{t}_{ÒÒ}^{\;}=4.57s$£¬¹Ê´ËʱÒÒ³µÔçÒѾͣÏÂÀ´£®
ÒÒ³µÍ£³µ¾àÀë${x}_{ÒÒ}^{\;}=\frac{{v}_{ÒÒ}^{2}-0}{2{a}_{ÒÒ}^{\;}}=\frac{{8}_{\;}^{2}-0}{2¡Á1.75}=\frac{128}{7}m$£¬Ôò±û³µÍ£³µ¾àÀë${x}_{±û}^{\;}={x}_{ÒÒ}^{\;}+6m=\frac{170}{7}m$¡¢ß
±û³µ¼ÓËÙ¶ÈΪ${a}_{±û}^{\;}=\frac{{v}_{±û}^{2}-0}{2{x}_{±û}^{\;}}=\frac{1{0}_{\;}^{2}-0}{2¡Á\frac{170}{7}}¡Ö2.06m/{s}_{\;}^{2}$¡¢à
´ð£º£¨1£©ÒÒ³µ¼õËÙÔ˶¯µÄ¼ÓËÙ¶È´óСÖÁÉÙӦΪ$1.75m/{s}_{\;}^{2}$
£¨2£©±û³µ¼õËÙÔ˶¯µÄ¼ÓËÙ¶È´óСÖÁÉÙӦΪ$2.06m/{s}_{\;}^{2}$
µãÆÀ ±¾ÌâÄѵãÔÚÓÚÓÐÈý¸öС³µ£¬¹Ø¼üÒª·ÖÁ½´ÎÇó½â£¬Ã÷È·ËÙ¶ÈÏàͬʱÓÐ×îС¾àÀ룬ѡÔñÇ¡µ±µÄÔ˶¯Ñ§¹«Ê½ºÜÖØÒª£®
| A£® | a¡¢bÁ½µã¼äµÄµçÊÆ²îUabΪ20V | |
| B£® | a¡¢bÁ½µã¼äµÄµçÊÆ²îUabΪ-20V | |
| C£® | µçºÉÔÚb´¦Ê±½«¾ßÓÐ4.0¡Á10-8JµÄµçÊÆÄÜ | |
| D£® | µçºÉµÄµçÊÆÄÜÔö¼ÓÁË4.0¡Á10-8J |
| A£® | ÓÐΨһֵ$\frac{mgtan¦È}{q}$ | B£® | ×îСֵÊÇ$\frac{mgsin¦È}{q}$ | C£® | ×î´óÖµ$\frac{mgtan¦È}{q}$ | D£® | $\frac{mg}{q}$ |
| A£® | Ù¤ÀûÂÔÑо¿×ÔÓÉÂäÌåÔ˶¯Ê±£¬Óöµ½µÄÀ§ÄÑÊÇÎÞ·¨×¼È·²âÁ¿Ë²Ê±ËÙ¶È | |
| B£® | Ù¤ÀûÂÔÑо¿×ÔÓÉÂäÌåÔ˶¯Ê±£¬Óöµ½µÄÀ§ÄÑÊÇÎÞ·¨×¼È·²âÁ¿¼ÓËÙ¶È | |
| C£® | ÔÚÎïÀíѧµÄ·¢Õ¹Àú³ÌÖУ¬Å£¶ÙÊ×ÏȽ¨Á¢ÁËÆ½¾ùËÙ¶È¡¢Ë²Ê±ËٶȺͼÓËٶȸÅÄîÓÃÀ´ÃèÊöÎïÌåµÄÔ˶¯ | |
| D£® | ÔÚÎïÀíѧµÄ·¢Õ¹Àú³ÌÖУ¬Ù¤ÀûÂÔÊ×ÏȽ¨Á¢ÁËÆ½¾ùËÙ¶È¡¢Ë²Ê±ËٶȺͼÓËٶȸÅÄîÓÃÀ´ÃèÊöÎïµÄÌåÔ˶¯ |
| A£® | СÎï¿é×îÖÕÍ£ÔÚˮƽ¶Î | |
| B£® | СÎï¿é»¬ÉÏÓÒ±ßÐ±Ãæ¶¥¶ËʱËÙ¶ÈÇ¡ºÃΪÁã | |
| C£® | СÎï¿é»¬ÉÏÓÒ±ßÐ±Ãæ¶¥¶ËʱËÙ¶ÈΪ$\sqrt{3}$ m/s | |
| D£® | СÎï¿é»¬ÉÏÓÒ±ßÐ±Ãæ¶¥¶ËʱËÙ¶ÈΪ2.7 m/s |
| A£® | ¼ÓËÙÓë¼õËÙµÄʱ¼ä²»Ò»¶¨ÏàµÈ | |
| B£® | ¼ÓËÙʱ¼äΪ10·ÖÖÓ | |
| C£® | ¼ÓËÙʱ¼ÓËÙ¶È´óСΪ0.56 m/s2 | |
| D£® | Èç¹û¼ÓËÙ¶È´óСΪ10 m/s2£¬ÌâÖÐËùÊöÔ˶¯×î¶ÌÐèÒª32·ÖÖÓ |