弹簧Ablockofmass0.711kgonaspringwithspringconstant239.1N/moscillatesverticallywithamplitude0.563m.Whatisthespeedofthisblockatadistanceof0.329mfromtheequilibriumposition?Alargeair-filled0.271-kgplasticballis

题目详情

弹簧
A block of mass 0.711 kg on a spring with spring constant 239.1 N/m oscillates vertically with amplitude 0.563 m.What is the speed of this block at a distance of 0.329 m from the equilibrium position?
A large air-filled 0.271-kg plastic ball is thrown up into the air with an initial speed of 11.3 m/s.At a height of 3.23 m,the ball's speed is 2.83 m/s.What fraction of its original energy has been lost to air friction?

▼优质解答

答案和解析

第一题比较复杂
首先求新平衡点位移x
Mg=kx 得到新的平衡点为x=0.029
再用能量守恒
0.5kx*2=mgh+0.5mv*2+0.5kx'*2
最终V是8.45m/s
第二题简单些,能量差等于空气阻力造成的能量流失
（0.5mv*2-mgh-0.5mv'*2）/E0 就好
最终能量流失44.14%

看了弹簧Ablockofmass...的网友还看了以下：

第二次 makefile 提示 make:`myapp' is up to date,myapp 　2020-05-16 …

O(∩_∩)O哈哈~O(∩_∩)O~(*^__^*)嘻嘻……那个可爱哦?对了撒~大家有一些可爱的网　2020-05-17 …

O/O+O/O+O/O=O/O+O/O,O/O表示几分之几,将1————10填入圆圈中,使式子成立　2020-06-06 …

.已知:Kps(ZnS)=1.2×10-23,Ksp(MnS)=1.4×10-15则()A.ϕo( 　2020-06-11 …

当x→0时，用o（x）表示比x高阶的无穷小，则下列式子中错误的是（）A．x•o（x2）=o（x3）　2020-06-14 …

当x→0时，用o（x）表示比x高阶的无穷小，则下列式子中错误的是（）A．xo（x2）=o（x3）B 　2020-06-18 …

如果O+O=U+U+U,O+Z=U+U+U+U,那么Z+Z+U=()个O.如果设U=6,那么O=( 　2020-06-18 …

根据单个字组句zhāo)昭(zhāo)沼(zhǎo)照(zhào)找(zhǎo)肇(zhào)韶( 　2020-07-10 …

弹簧Ablockofmass0.711kgonaspringwithspringconstant2 　2020-07-19 …

想一想,填一填.1.OX三角=口O+O+O=口—O—O三角=（?）2.O—口=想一想,填一填.1.O 　2020-11-04 …