百度试题 结果1 题目What is the force that pulls objects towards the center of the Earth? A. Friction B. Gravity C. Magnetism D. Electricity 相关知识点: 试题来源: 解析 B。解析:重力是使物体向地球中心下落的力。反馈 收藏
A friction coefficient refers to the value that quantifies the level of friction between two surfaces in different environmental conditions. It is determined by comparing the variations of the coefficient measured during tests conducted at different temperatures and environments. ...
aIn the air the ball still has inertia. It’s going to keep moving in the same direction at the same speed until a force makes it do otherwise. Well, the force of gravity pulls it toward the ground in a curved path, like Galileo’s cannonball. Also, the force of friction with air...