関連ワード:  why work done is a vector quantity    why work done is a scalar quantity    why work done is a scalar quantity class 9    why work done is not a vector quantity    work done is a vector quantity true or false    why does work done a scalar quantity    work done is a scalar quantity true or false    work done is a scalar quantity or not    work done is a scalar quantity which cannot be negative like mass    work done is a scalar quantity justify