4.6 teachers, additional knowledge to the students that the mechanical device that is causing the result object, or gives birth to lessen. In addition, we also bring machinery is used to change the direction of movement. Change the speed The students will learn about machinery, called "simple machine" in other learning activities.
การแปล กรุณารอสักครู่..
![](//thimg.ilovetranslation.com/pic/loading_3.gif?v=b9814dd30c1d7c59_8619)