Читать книгу String Theory For Dummies - Andrew Zimmerman Jones - Страница 99

Newton’s second law of motion, and the way it relates force, acceleration, and mass, is the only law of motion relevant to a string theory discussion. However, for true Newton-o-philes, here are the other two laws of motion, paraphrased for ease of understanding:

 Newton’s first law of motion: An object at rest remains at rest, or an object in motion remains in motion, unless acted upon by an external force. In other words, it takes a force to cause motion to change.

 Newton’s third law of motion: When two objects interact through a force, each object exerts a force on the other object that is equal and opposite. In other words, if we exert a force on a wall with a hand, the wall exerts an equal force back on the hand.