{"id":9455,"date":"2026-06-01T21:33:48","date_gmt":"2026-06-01T21:33:48","guid":{"rendered":"https:\/\/kapdec.com\/help\/?p=9455"},"modified":"2026-06-01T21:33:48","modified_gmt":"2026-06-01T21:33:48","slug":"fundamental-forces","status":"publish","type":"post","link":"https:\/\/kapdec.com\/help\/fundamental-forces\/","title":{"rendered":"Fundamental Forces"},"content":{"rendered":"

Unit: <\/strong>Circular Motion and Gravitation<\/strong><\/h2>\n

Chapter: Fundamental forces<\/strong><\/h3>\n

Reference: AP Physics Algebra, <\/em>Fundamental forces Circular Motion and Gravitation, Force Contact forces, Newton’s First Law of Motion, Newton’s Second Law of Motion, Newton’s Third Law of Motion,<\/p>\n

After studying this chapter, you should be able to:<\/strong><\/p>\n

    \n
  • state Newton’s laws<\/li>\n
  • solve the problem related to Newton’s laws<\/li>\n<\/ul>\n

    Force:<\/strong><\/p>\n

    A force is a push or pulls acting on a body. It is a vector quantity i.e. it has both magnitude and direction.<\/p>\n

    Unit of Force: <\/strong>Its unit is Newton in SI system and Dyne in CGS system.<\/p>\n

    Dimensions<\/strong>:      MLT <\/sub>–<\/sup>2<\/sup><\/p>\n

     (a)Contact Forces:<\/strong> Tension, Normal Reaction, Friction etc. Forces that act between bodies in contact.<\/p>\n

     (b)Field forces (non-contact forces):<\/strong> Weight, electrostatic forces, etc.  Forces that act between bodies separated by a distance without any actual contact.<\/p>\n

    Contact forces:<\/strong><\/p>\n

    Contact forces are the forces that act between two objects in contact with each other. These forces arise due to the interaction between the molecules of the two objects at the point of contact. The magnitude and direction of contact forces depend on various factors such as the nature of the surfaces in contact, the force applied, and the angle of contact.<\/p>\n

    Some common examples of contact forces are:<\/p>\n

    Frictional force:<\/strong> This force arises due to the interaction between the surfaces of two objects in contact when they move or try to move relative to each other. Frictional force opposes the motion and is proportional to the normal force exerted by the objects on each other.<\/p>\n

    Normal force:<\/strong> This force is perpendicular to the surface of contact and arises due to the repulsive interaction between the molecules of the two objects in contact. The normal force is equal in magnitude and opposite in direction to the force applied by one object on the other.<\/p>\n

    \"\"<\/p>\n

    Tension force:<\/strong> This force arises when an object is pulled or pushed by a rope, cable, or any other material in tension. The magnitude of the tension force is equal to the force applied by the material on the object.<\/p>\n

    Elastic force:<\/strong> This force arises when an object is deformed or compressed by another object. The magnitude of the elastic force is proportional to the deformation or compression.<\/p>\n

    Shear force:<\/strong> This force arises when two objects slide past each other in opposite directions. The magnitude of the shear force is proportional to the area of contact and the force applied.<\/p>\n

    Understanding contact forces is important in various fields such as physics, engineering, and material science.<\/p>\n

     <\/p>\n

    Newton’s First Law of Motion:<\/strong><\/p>\n

    Everybody continues in its state of rest, or of uniform motion in a straight line, unless it is compelled to change that state by an external force.<\/p>\n

    Inertia<\/strong><\/p>\n

    Inertia is the property of a body by virtue of which a body retains its state: either of rest or uniform motion along a straight line.<\/p>\n

    Momentum<\/strong><\/p>\n

    It is equal to the product of the mass and the velocity of the body. Its direction is the same as the velocity of the body.<\/p>\n

             p<\/em>=m<\/em>v<\/em>
    \n        where  
    \n      p<\/em>\"\" = momentum of the body.<\/p>\n

             m = mass of the body.<\/p>\n

             v<\/em>\"\" = velocity of the body.<\/p>\n

    Unit: Its unit is kg-m\/s in SI system and gm-cm\/s in CGS system.<\/p>\n

    Dimensions: Its dimension is MLT-1<\/sup><\/p>\n

    Newton’s Second Law of Motion:<\/strong><\/p>\n

    Newton’s second law states that the rate of change of momentum of a body is directly proportional to the applied force.<\/p>\n

    \"\"<\/p>\n

    Where k is the constant of proportionality.<\/p>\n

    Unit force is now defined as that force which produces a unit rate of change of momentum in a body<\/p>\n

    \"\"<\/p>\n

     <\/p>\n

    Newton’s Third Law of Motion:<\/strong><\/p>\n

    The third law states that for every action, there is an equal and opposite reaction. This means that whenever one object exerts a force on another object, the second object exerts an equal and opposite force back on the first object. Every action has an equal and opposite reaction.<\/p>\n

     <\/p>\n

    Key Points:<\/strong><\/p>\n

      \n
    • Frictional force:<\/strong> This force arises due to the interaction between the surfaces of two objects in contact when they move or try to move relative to each other. Frictional force opposes the motion and is proportional to the normal force exerted by the objects on each other.<\/li>\n
    • Normal force:<\/strong> This force is perpendicular to the surface of contact and arises due to the repulsive interaction between the molecules of the two objects in contact. The normal force is equal in magnitude and opposite in direction to the force applied by one object on the other.<\/li>\n
    • Tension force:<\/strong> This force arises when an object is pulled or pushed by a rope, cable, or any other material in tension. The magnitude of the tension force is equal to the force applied by the material on the object.<\/li>\n
    • Elastic force:<\/strong> This force arises when an object is deformed or compressed by another object. The magnitude of the elastic force is proportional to the deformation or compression.<\/li>\n
    • Shear force:<\/strong> This force arises when two objects slide past each other in opposite directions. The magnitude of the shear force is proportional to the area of contact and the force applied.<\/li>\n<\/ul>\n

       <\/p>\n

        \n
      • The first law, also known as the law of inertia, states that an object at rest will remain at rest, and an object in motion will continue to move in a straight line at a constant speed unless acted upon by an external force. In other words, objects tend to resist changes in their state of motion.<\/li>\n<\/ul>\n

         <\/p>\n

          \n
        • The second law states that the force applied to an object is directly proportional to its mass and acceleration. This law is expressed mathematically as F=ma, where F is the force, m is the mass of the object, and a is the acceleration.<\/li>\n<\/ul>\n

           <\/p>\n

            \n
          • The third law states that for every action, there is an equal and opposite reaction. This means that whenever one object exerts a force on another object, the second object exerts an equal and opposite force back on the first object.<\/li>\n<\/ul>\n

             <\/p>\n","protected":false},"excerpt":{"rendered":"

            Unit: Circular Motion and Gravitation Chapter: Fundamental forces Reference: AP Physics Algebra, Fundamental forces Circular Motion and Gravitation, Force Contact forces, Newton’s First Law of Motion, Newton’s Second Law of Motion, Newton’s Third Law of Motion, After studying this chapter, you should be able to: state Newton’s laws solve the problem related to Newton’s laws […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[622],"tags":[],"class_list":["post-9455","post","type-post","status-publish","format-standard","hentry","category-ap-physics-1"],"_links":{"self":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/posts\/9455","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/comments?post=9455"}],"version-history":[{"count":0,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/posts\/9455\/revisions"}],"wp:attachment":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/media?parent=9455"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/categories?post=9455"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/tags?post=9455"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}