Newton's Law of Motion

• What are Newton's Laws of Motion primarily concerned with?

  They describe the relationship between the motion of an object and the forces acting on it.
• What is a frame of reference?

  A frame of reference is a system for specifying the precise location of objects in space and time.
• What does the law of inertia state?

  An object at rest stays at rest, and an object in motion stays in motion unless acted upon by a net external force.
• How does the law of acceleration relate force and mass?

  The law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.
• What is the law of action-reaction?

  For every action, there is an equal and opposite reaction.
• What is a free-body diagram?

  A free-body diagram represents all the forces acting on a single object.
• What is weight in physics?

  Weight is the force of gravity acting on a mass.
• How do you calculate the weight of a 4.0 kg mass on the surface of the Moon?

  Weight = mass × gravitational acceleration on the Moon.
• What is friction?


  Friction is a contact force that resists the motion of an object.
• What is static frictional force?


  Static frictional force exists when an object is at rest and opposes impending motion.
• What is kinetic frictional force?

  Kinetic frictional force exists while an object is in motion.
• If a horizontal force of 85 N is required to pull a child in a sled at constant speed, what does this indicate about the forces acting on the sled?

  This indicates that the force of friction is equal to 85 N.
• What is the normal force?

  The normal force is the reaction force exerted by a surface perpendicular to the object resting on it.
• When was Newton's "Principia Mathematica" published?

  It was published in 1686.
• What does Newton's first law of motion describe?

  It describes the conditions under which an object remains at rest or in uniform motion.
• What does Newton's second law of motion state?

  It states that the acceleration of an object is proportional to the net force acting on it and inversely proportional to its mass.
• How do you solve problems using Newton's second law of motion?

  By applying the formula \( F = ma \), where \( F \) is the net force, \( m \) is the mass, and \( a \) is the acceleration.
• What is the focus of Newton's third law of motion?

  It focuses on the action-reaction pairs of forces.
• What are forces in an inclined plane?

  Forces in an inclined plane involve the components of gravitational force acting parallel and perpendicular to the surface of the incline.
• How do you analyze a pulley mass system?

  By applying Newton's laws to determine the forces acting on each mass and the resulting acceleration.
• How do you find the resultant acceleration of an object being pulled by multiple forces?

  By using a scale diagram to combine the forces and apply Newton's second law.
• If a student weighs 825 N, how do you find their mass?

  By using the formula \( m = \frac{F}{g} \), where \( F \) is the weight and \( g \) is the acceleration due to gravity.
• How do you calculate the coefficient of kinetic friction between the sled and the snow?


  By using the formula \( \mu_k = \frac{F_f}{N} \), where \( F_f \) is the force of friction and \( N \) is the normal force.
• What are the types of forces in physics?

  • Contact Forces:
  • Frictional force
  • Tensional force
  • Spring force
  • Normal force
  • Noncontact Forces (Field Forces):
  • Electrostatic force
  • Gravitational force
  • Magnetic force
• What are the different types of friction?

  • Static Frictional Force: Exists when starting to move an object from rest.
  • Limiting Frictional Force: Maximum value of static friction at the verge of starting motion.
  • Kinetic Frictional Force: Exists while the object is moving.
• What are the key components of Newton's Laws of Motion?

  1. First Law: Law of Inertia
  2. Second Law: \( F = ma \)
  3. Third Law: Action-Reaction principle
• What are the steps to solve gravitational force or weight problems?


  1. Identify the mass of the object.
  2. Use the formula \( W = mg \) where \( g \) is the acceleration due to gravity.
  3. Calculate the weight.
• What are the steps to solve frictional force problems?

  1. Identify the forces acting on the object.
  2. Use the formula \( F_f = \mu_k N \) where \( \mu_k \) is the coefficient of kinetic friction and \( N \) is the normal force.
  3. Calculate the required force to overcome friction.
• Law of Inertia


  An object at rest or in uniform motion will remain at rest or in uniform motion unless acted upon by external force.
• Law of Interaction 


  For every action, there is an equal and opposite reaction.
• Law of Acceleration 


  the acceleration of an object is directly proportional to the net force and inversely proportional to its mass