関連ワード:  speed is a scalar or vector quantity    speed is a scalar or vector quantity give reason    speed is a scalar or vector quantity give reason for your choice    is speed a scalar or vector quantity explain    is speed a scalar or vector quantity justify your answer    force is a scalar or vector quantity    mass is a scalar or vector quantity    velocity is a scalar or vector quantity    force is a scalar or vector quantity explain    average speed is a scalar or vector quantity