In order to slide a heavy desk across the floor at constant speed in a straight line, you have to exert a horizontal force of 40
0 Newtons. Compare the 400-Newton horizontal pushing force F to the frictional force f between the desk and the ground. 1. F < f; the frictional force is greater than the pushing force since it is such a heavy desk.
2. F = f from Newton’s first law.
3. F > f; the frictional force is always less than any other force acting on the object.
4. It depends on the direction the desk moves. 5. F = f from Newton’s third law.
since the desk is moved in a straight line at a constant speed, newton first law tell us that the two forces must be equal.
Newton's First Law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. since the table has been set in motion by the 400 N force, it will remain in motion unless it is been acted upon by an external force, and this means that the 400 N must be equal to the frictional force for it to have been in motion in the first instance.
Are you referring to the fact that water is a compound while hydrogen is an element? If I'm wrong just comment and clarify and I can edit it, I don't even know what kind of unit you're in. :)
