资讯
A free body diagram models the forces acting on an object. The object or 'body' is usually shown as a box or a dot. The forces are shown as thin arrows pointing away from the centre of the box or dot.
The human body comes in lots of different shapes and sizes but most are made up of the same parts which do the same job. We all have a skeleton. The bones in your skeleton help you stay standing ...
一些您可能无法访问的结果已被隐去。
显示无法访问的结果