Physics

F = ma係牛頓第一定律
計既係average acting on the object,
佢都等於rate of change of momentum

mgh係potential energy, 即係勢能
計既係potential energy

彈性碰撞即係兩樣物件碰撞後無energy loss
非彈性碰撞就有energy loss
邊條方程就要睇情況而定

動量守恆 = conservation of momentum
方程: m1u1 + m2u2 = m1v1 + m2v2
意思係係一個system入面, 如果無外力acts upon the system,
initial momentum = final momentum

能量守恆 = conservation of energy
意思既係within一個system入面,
無論個energy係以咩形式存在,
佢所有能量既總和都係一樣
方程都係視情況而定