Which of the following is NOT a non-contact force?

The correct answer is Option 3. 

Key Points

• Friction is a contact force, not a non-contact force.
• It is the force that opposes the motion or potential motion between two surfaces in contact with each other.
• Examples of contact forces include friction between objects, normal force, tension in a rope, and applied force.

Additional Information

• Gravitational force is a non-contact force.
  • It is the force of attraction between two objects with mass.
  • It acts at a distance without the need for physical contact between the objects.
  • The force of gravity is responsible for the motion of celestial bodies, such as the planets orbiting the sun, and the gravitational attraction between objects on Earth.
  • It follows Newton's law of universal gravitation, which states that the force of gravity is proportional to the product of the masses of the objects and inversely proportional to the square of the distance between them.
• Electrostatic force is also a non-contact force.
  • It is the force of attraction or repulsion between electrically charged particles.
  • Like gravitational force, electrostatic force acts at a distance without the need for physical contact between the charged objects.
  • It is responsible for various phenomena, such as the interaction between charged particles, the attraction of hair to a charged comb, and the repulsion between like charges.
  • Electrostatic force follows Coulomb's law, which states that the force between two charged objects is directly proportional to the product of their charges and inversely proportional to the square of the distance between them.
• Magnetic force is another example of a non-contact force.
  • It is the force of attraction or repulsion between magnetic objects or between a magnetic object and a moving charged particle.
  • Magnetic force acts at a distance without the need for physical contact between the objects involved.
  • This force is associated with magnetic fields and is responsible for various phenomena, such as the interaction between magnets, the behavior of compass needles, and the deflection of charged particles in magnetic fields.
  • The strength and direction of the magnetic force depend on the magnetic properties and relative orientations of the objects or particles involved.