体积为3×10﹣4米3的金属块浸没在水中.
求:(1)该金属块排开水的体积V排.
(2)该金属块所受到的浮力F浮.
如图所示,用滑轮组提升重物用笔画线代替绳子在图中画出最省力的绳绕法。
完形填空
Look at this girl. 1 name is Wang Meimei. 2 is twelve. Wang Ming is her brother. He is3 Class Three,Grade Two. Do you know how old he is? He is fourteen years old. The brother4 sister are in No. 2 Middle School. Their mother5 a teacher. She is an6 teacher. Their father, Mr Wang, is a teacher, 7. He is a Chinese teacher in No. 8 Middle School. Their students all love them because they love their students. They have(有) a cat.8 name is Mimi. 9 a nice cat. The cat and Wang Meimei are 10friends.
利用计算器求值(结果精确到0.001):sin55°≈____ ;tan45°23′≈____ .