Trường hợp nào dưới dây có thể coi là chất điểm A. trái đất trong CĐ tự quay quanh mình nó với nhau
B. hai hòn bi lúc va chạm
C. người nhảy cầu lúc đang rơi xuống nước
D. giọt nước mưa lúc đang rơi

Explain how the energy of rubber ball is tranforned as it roll down a ramp. give evidence that the energy of the og the ball remains the same at all points on the ramp

Under the action of a constant force an object accelerates at 7.8 m/s2. what will the acceleration be if (a) the force is halved? (b) the object's mass is halved? (c) the force and the object's mass are both halved? (d) the force is halved and the object's mass is doubled?

When electrons are added to the outermost shell of a carbon atom, it forms--an anion that has a larger anion that has a smaller cation that has a larger cation that has a smaller radius.