CONCEPT: - Force: Force is an external effect in the form of a push or pulls that: 1. Produces or tries to produce motion in a body at rest. 2. Stops or tries to stop a moving body. 3. Changes or tries to change the direction of motion of the body. There are two types of forces based on their applications: - Contact forces are those types of forces that result when the two interacting objects are in contact with each other physically. - Example: Friction force, tension force, Normal force, etc. - Non-Contact Force - It is a force that acts on an object without coming physically in contact with it. - eg: Gravitational Force, Electrostatic force, Magnetic force EXPLANATION: - The magnetic force is the force exerted by the charged body when it moves in a magnetic field. It is called non-contact force because it attracts the objects which do not require that objects in physical contact with each other. - The frictional force is a contact force between two surfaces that are trying to move relative to each other (static friction) or is moving relative to each other (kinetic friction). Therefore option 1 is correct.