唉我真係攰了
Barbell個 force 係嗰個數,唔代表你hold equilibrium 就係岀返嗰個 magnitude 嘅數,因為 force 係 vector,你畀嘅 counter force 係會 based on 個角度用 trigo 扣返,記唔記得中學用過嘅 sin cos graph
你都識講手腕招財貓咁揸住支 bar 會易啲,唔係因為你啲餅減咗磅,係因為你減細咗個手腕岀嘅力同支 bar 嘅力嘅 angle (again force is a vector)。你記唔記得中學教過 cos0 係 1 cos90 係 0,你畀嘅力如果係 exactly opposite in direction to 支 bar 畀嘅力,個力同支bar嘅力就1:1,啫係我所講嘅「順住前臂嘅方向」,otherwise 就會有個lateral force 係你嘅手腕要 counter balance (aka 岀力) 去達至
equilibrium
好喇講上同落,點解你嗰句腳食唔到力就落晒手腕唔 make sense,因為無論手腕點放都好,只要手腕同支bar in equilibrium (啫係對於一舊嘢,另一舊嘢冇郁過),就代表手腕冇 net upwards/downward force
against the bar,based on that 你上落嘅加減速度係由你對腳 provide.
最後點解話你個盲目追重論冇邏輯,因為 based on 上段個「加減速度係由你對腳 provide」,你要練squats 就應該係對腳做 limiting factor,唔係手腕,Wrist guard 就係用嚟 counter balance 個 lateral force
呢啲 DSE physics嚟,你温吓書先喇好嘛