Law of inertia and law of accelaration (science)

• Newton's First Law of Motion

  • Law of Inertia
• Newton's Second Law of Motion

  Law of Acceleration
• Motion has been a very familiar and common concept to all even before one has learned to walk
• The measure of an object's inertia is its mass
• The Law of Inertia best explains why light objects move faster than heavy objects when equal force is applied
• An object placed on top of the table at rest is because the forces are balanced with zero net force
• A bicycle would less likely do harm to a tree when it crashes into it compared to a bus, motorcycle or taxi when moving at the same speed
• Unloading passengers may decrease the acceleration of a jeepney
• Relationship between mass and acceleration

  Inverse
• Net force causes an object to accelerate
• Inertia increases as the mass increases
• The carabao has the greatest inertia while at rest compared to a cat, chicken or pig
• The concept of wearing seatbelts while riding in a car is based on Newton's Law of Inertia
• Examples of exerting a force


  • A carpenter hammering a nail
• A change in motion that produces acceleration is a speed skater moving at a constant speed on a straight track
• The ball with a mass of 0.52 kg will have the greater acceleration when a force of 26 N is exerted on both balls
• The acceleration of a 5-kg block with a 20-N force acting on it is 4 m/s^2
• The force of gravity pulls down on the book with a force of 20 newtons, but the table prevents the book from accelerating downward
• Inertia


  An inherent property of an object to resist change
• An object's mass


  The more mass an object has, the more inertia or resistance to change in motion it has
• Newton's First Law of Motion (Law of Inertia)

  An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues to move with the same velocity unless acted on by an unbalanced force.
• An unbalanced force can cause an object at rest to move
• Newton's Second Law of Motion (Law of Acceleration)

  The acceleration of an object is directly proportional to the net force on it and inversely proportional to its mass.
• Force (F)


  The product of mass (m) and acceleration (a)
• Mass (m)


  The measure of the amount of matter in an object
• Acceleration (a)


  The rate of change of velocity per unit of time
• 1 Newton


  The amount of force that will accelerate a 1 kg mass at the rate of 1 m/s^2
• Sample problems using the formula for the Law of Acceleration

  • Car with acceleration of 7 m/s^2 and mass of 80.5 kg, find the force

  2. Car pulled with 10,500 N force and acceleration of 2 m/s^2, find the mass

  3. Object with 48 N force and 12 kg mass, find the acceleration
• Activity 2.1: Problem Solving (F=ma)

  Given, Asked, Formula, Solution, Answer
• Activity 2.2: Completing statements about Newton's First Law of Motion


  Law of Inertia

  2. rest, rest, velocity, speed, direction, unbalanced

  3. An inherent property of an object to resist change
• Skateboard


  Mass of 2 kg, accelerates at 6 m/s²
• Unbalanced force


  Amount of force required to cause the skateboard's acceleration
• Truck


  Pulled with a force of 20,500 Newtons, acceleration rate of 4 m/s²
• Mass of the truck


  Unknown, needs to be calculated
• Swimmer


  Mass of 70 kg, pushes off wall with 350N of force
• Swimmer's acceleration rate


  Unknown, needs to be calculated
• Newton's First Law of Motion


  Also known as the Law of Inertia
• Statements about Newton's First Law

  • An object at rest stays at rest unless acted on by an unbalanced force
  • An object in motion keeps moving with constant velocity unless acted on by an unbalanced force
• Inertia


  The resistance of an object to changes in its state of motion
• Mass


  The property of an object that determines how much inertia it has