¡¾´ð°¸¡¿
·ÖÎö£º£¨1£©Óÿ̶ȳ߲âÁ¿ÎïÌ峤¶Èʱ£¬Õý·½Ì峤¶ÈµÈÓÚÓÒ²àËù¶Ô¿Ì¶È¼õÈ¥×ó²àËù¶Ô¿Ì¶È£¬ÖªµÀ±ß³¤£¬ÀûÓù«Ê½V=a
3£¬Äܹ»µÃµ½Ìå»ý£»Ê¹ÓÃÌìƽʱ£¬ÎïÌåÖÊÁ¿µÈÓÚíÀÂë×ÜÖÊÁ¿¼ÓÉÏÓÎÂëËù¶ÔµÄ¿Ì¶È£»ÖªµÀÁËÖÊÁ¿ºÍÌå»ý£¬ÓæÑ=
Äܹ»¼ÆËãÕý·½ÌåÃܶȣ®
£¨2£©¹ÌÌå¶ÔÖ§³ÖÃæµÄѹǿÓù«Ê½P=
¼ÆË㣬ÆäÖÐѹÁ¦µÈÓÚÎïÌåµÄÖØÁ¦£¬ÊÜÁ¦Ãæ»ýÊÇÎïÌåÓë×ÀÃæµÄ½Ó´¥Ãæ»ý£¬¶ø²»ÊÇ×ÀÃæµÄÃæ»ý£®
£¨3£©ÎïÌåÊܵ½µÄ¸¡Á¦Óù«Ê½F
¸¡=¦Ñ
ÒºgV
ÅÅ·ÖÎö£¬ÒÑÖªÎïÌåÅÅ¿ªË®µÄÌå»ýÊÇÎïÌåÌå»ýµÄ
£®
£¨4£©¶¯»¬ÂֵĻúеЧÂÊÓù«Ê½¦Ç=
¼ÆË㣬ÆäÖÐW
ÓÐÓÃÊÇ»¬ÂÖ¶ÔÎïÌå×öµÄ¹¦£¬ÓÃW=Gh¼ÆË㣻W
×ÜÊǵ¯»É²âÁ¦¼Æ¶ÔÉþ×Ó×öµÄ¹¦£¬ÓÃW=FS¼ÆË㣮ÀÁ¦×öµÄ¹¦ÊÇ×ܹ¦£¬ËùÒÔ¼ÆËãÀÁ¦µÄ¹¦ÂÊʱ£¬Óù«Ê½P=
£®
½â´ð£º½â£º£¨1£©Õý·½ÌåµÄ±ß³¤ÊÇ3cm£¬
Õý·½ÌåµÄÌå»ýΪ
V=a
3=£¨3cm£©
3=27cm
3
Õý·½ÌåµÄÖÊÁ¿ÊÇ162g£»
Õý·½ÌåµÄÃܶÈΪ
¦Ñ=
=
=6g/cm
3
£¨2£©Õý·½Ìå¶Ô×ÀÃæµÄѹÁ¦Îª
F=G=mg=0.162kg×10N/kg=1.62N
Õý·½ÌåÓë×ÀÃæµÄ½Ó´¥Ãæ»ýΪ
S=a
2=£¨3×10
-2m£©
2=9×10
-4m
2
Õý·½Ìå¶Ô×ÀÃæµÄѹǿΪ
P=
=
=1800Pa
£¨3£©Õý·½ÌåÅÅ¿ªË®µÄÌå»ýΪ
V
ÅÅ=
V=
×27cm
3=13.5×10
-6m
3
Õý·½ÌåÊܵ½µÄ¸¡Á¦Îª
F
¸¡=¦Ñ
ˮgV
ÅÅ=1.0×10
3kg/m
3×10N/kg×13.5×10
-6m
3=0.135N
£¨4£©Éþ×Ó×ÔÓɶËÒƶ¯µÄ¾àÀëΪS=2h=2×0.5m=1m
¶ÔÎïÌå×öµÄÓÐÓù¦Îª
W
ÓÐÓÃ=Gh=1.62N×0.5m=0.81J
ÀÁ¦×öµÄ¹¦Îª
W
×Ü=FS=1.2N×1m=1.2J
»úеЧÂÊΪ
¦Ç=
=
=67.5%
ÀÁ¦µÄ¹¦ÂÊΪ
P=
=
=0.12W
´ð£º
£¨1£©´ËÎïÌåµÄÃܶÈΪ6g/cm
3£»
£¨2£©ÎïÌå¶Ô×ÀÃæµÄѹǿΪ1800Pa£»
£¨3£©ÎïÌåÊܵ½µÄ¸¡Á¦Îª0.135N£»
£¨4£©¶¯»¬ÂֵĻúеЧÂÊΪ67.5%£¬ÀÁ¦µÄ¹¦ÂÊΪ0.12W£®
µãÆÀ£ºÀûÓÃP=
¼ÆËã¹ÌÌå¶ÔÖ§³ÖÃæµÄѹǿʱ£¬ÒªÃ÷È·SµÄº¬Ò壺ÎïÌåÓëÖ§³ÖÃæµÄ½Ó´¥Ãæ»ý£¬²»Ò»¶¨µÈÓÚÎïÌå»òÖ§³ÖÃæµÄÃæ»ý£®