動量：p＝mv ｛p:動量(kg/s)，m:質量(kg)，v:速度(m/s)，方向與速度方向相同｝ ，是矢量。
Momentum: p = mv (p: momentum (kg / s), m: mass (kg), v: velocity (m / s), direction and speed in the same direction) is a vector.
2.簡述牛頓第三定律。
牛頓第三定律： 兩個物體間的作用力和反作用力總是大小相等，方向相反，並且作用在同壹直線上 。F1＝－F2
①力的作用是相互的。同時出現，同時消失。
②相互作用力壹定是相同性質的力
③作用力和反作用力作用在兩個物體上，產生的作用不能相互抵消。
④作用力也可以叫做反作用力，只是選擇的參照物不同
⑤作用力和反作用力因為作用點不在同壹個物體上，所以不能求合力
Newton's Third Law: the force between two objects and reaction are always equal and opposite, and the role of a straight line. F1 =- F2
① force's role is mutual. Also appear at the same time disappear.
② interaction force must be of the same nature
③ reaction force and the role of the two objects, the resulting effect can not cancel each other out.
④ called the reaction force can only choose different reference
⑤ force and reaction force acting point is not the same as an object, it can not seek together
3 如果壹個箱子向右側滑動，求摩擦力的方向？
左
Left
4 陳述壹下質量和重量的壹點區別
1．定義不同。質量是物體慣性的量度，它是任何物體都固有的壹種屬性。重量則反映了物體所受重力的大小，它是受地球的吸引而引起的。
2．質量是標量。重量是矢量。
1. Different definition. Quality is the measure of inertia an object, any object which is an inherent property of all. Suffered weight reflects the gravity of the size of the object, it is attracted by the Earth caused.
2. Quality is the scalar. Weight vector.