Newtons Laws In Mechanics

The coefficient of static friction between a book and a desk surface is 0.6. The book wdgjbs 20 N. If a horizontal force of 10 N is applied to the book, would the book move And if not, what is the magnitude of the friction force What should be the magnitude of the horizontal force to set the book in motion  

Since the magnitude of the horizontal force (10 N) is less than the maximum friction force (12 N), the book will not move, and hence the friction force will equal the applied force. A horizontal force having a mt nimde greater than 12 N will be required to set the book in motion. 

As we mentioned in Chapter 6, physical laws are based on observations. In this section, we will briefly discuss Newton s laws, which form the foundation of mechanics. The design and analysis of many engineering problems, including structures, machine parts, and the orbit of satellites, begins with the application of Newton s laws. Most of you will have the opportunity to take a physics, statics, or dynamics class that will explore Newton s laws and their applications further. 

If a given object is at rest, and if there are no unbalanced forces acting on it, the object will then remain at rest. If the object is moving with a constant speed in a certain direction, and if there are no unbalanced forces acting on it, the object will continue to move with its constant speed and in the same direction. Newton s first law is quite obvious and should be intuitive. For example, you know from your everyday experiences that if a book is resting on a table and you don t push, pull or lift it, then the book will lie on that table in that position until it is disturbed with an unbalanced force. 

We briefly explained this law in Chapter 6, where we said that if you place a book on a smooth table and push it hard enough, it will move. Newton observed this and formulated his observation into what is called Newton s second law of motion. Newton observed that as he increased 

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