Law of Acceleration

• Newton's second law of motion

  The net force on an object is equal to the product of its mass and acceleration
• Acceleration


  The rate at which the velocity of a body changes with time
• Law of acceleration


  1. F=ma

  2. F=ma
• F is the net force in N or dyn, m is the mass in kg or g, and a is the acceleration in m/s² or cm/s²
• Sample problem


  1. Given: m=50 kg, F=250 N, Friction=40 N

  2. Calculate acceleration
• Acceleration of 4.2 m/s² means the cabinet's speed increases by 4.2 m/s every second
• When the net force increases and mass remains the same

  Acceleration increases
• When equal net force acts on two objects

  The object with greater mass has lower acceleration
• When net force is constant and mass decreases

  Acceleration increases
• In maintaining acceleration, if mass increases the net force should also increase, if mass decreases the net force should also decrease
• Falling objects of different masses have the same acceleration due to gravity (approximately 9.8 m/s²)
• Newton's second law for objects under gravity

  F=mg
• Gravitational force is proportional to the mass of the object
• If mass doubles


  Gravitational force doubles
• Newton's second law applies to objects in uniform circular motion
• Centripetal force


  Any force that pulls the object toward the center of the circle, causing it to follow a circular path
• Centripetal force alters the direction of the object without changing its speed