force and laws of motion

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my ppt is based on forces and laws of motion and related to physics...hope u guyz will like it!

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force and laws of motion

  1. 2. FORCE <ul><li>A PUSH OR PULL ON A BODY IS CALLED FORCE. </li></ul><ul><li>FORCES ARE USED IN OUR EVERYDAY ACTIONS LIKE PUSHING, PULLING, LIFTING, STRECHING, TWISTING AND PRESSING. </li></ul>
  2. 3. EFFECTS OF FORCE <ul><li>A force cannot be seen. A force can be judged only by the effects which it can produce in various bodies (or objects) around us. </li></ul><ul><li>A force can move a stationary body. </li></ul><ul><li>A force can stop a moving body. </li></ul><ul><li>A force can change the speed of a moving body. </li></ul><ul><li>A force can change the direction of a moving body. </li></ul><ul><li>A force can change the shape and size of a body. </li></ul>
  3. 4. BALANCED AND UNBALANCED FORCE <ul><li>THERE ARE TWO KINDS OF FORCE: </li></ul><ul><li>1. BALANCED FORCE. </li></ul><ul><li>2. UNBALANCED FORCE. </li></ul>
  4. 5. BALANCED FORCES <ul><li>If the resultant of all the forces acting on a body is zero, the forces are called balanced forces. </li></ul><ul><li>If a number of balanced forces act on a stationary body, the body continuous to remain in its stationary position. </li></ul><ul><li>If a number of balanced forces act on a body in uniform motion, the body continuous to be in its state of uniform motion. </li></ul><ul><li>Though balanced forces cannot produce motion in a stationary body but can change the shape of the body. </li></ul>
  5. 6. UNBALANCED FORCE <ul><li>If the resultant of all the forces acting on a body is not zero, the forces are called unbalanced forces. </li></ul><ul><li>When an unbalanced force acts on a body, it produces motion in the body. Also, an unbalanced can stop a moving body. </li></ul><ul><li>If there were no unbalanced force of friction or air resistance, a moving body would go on for ever. </li></ul>
  6. 7. NEWTON’S LAW OF MOTION <ul><li>NEWTON HAS GIVEN THREE LAWS OF TO DEFINE THE MOTION OF BODIES. THESE LAWS ARE KNOWN AS NEWTON’S LAWS OF MOTION. </li></ul>
  7. 8. NEWTON’S FIRST LAW OF MOTION <ul><li>A body at rest will remain in rest, and a body in motion will continue in motion in a straight line with uniform speed, unless it is compelled by an external force to change its state of rest or of uniform motion. </li></ul><ul><li>INERTIA: Inertia is that property of a body due to which it resists a change in its state of rest or of uniform motion. </li></ul>
  8. 9. MOMENTUM <ul><li>The momentum of a body is defined as the product of its mass and velocity. </li></ul><ul><li>NOTE: the force required to stop a moving body is directly proportional to its mass and velocity. </li></ul><ul><li>Thus, momentum= mass x velocity </li></ul><ul><li>or, p= m x v </li></ul><ul><li>where p= momentum </li></ul><ul><li>m= mass of the body and, v = speed of the body </li></ul><ul><li>SI UNIT = the SI unit of momentum is kilogram meters per second (kg.m/s) </li></ul>
  9. 10. NEWTON’S SECOND LAW OF MOTION <ul><li>The rate of change of momentum of a body is directly proportional to applied force, and takes place in the direction in which force acts. </li></ul><ul><li>Force= change in momentum/time taken </li></ul><ul><li>f= mv-mu/t </li></ul><ul><li>f= m(v-u)/t. But we know that v-u/t =a </li></ul><ul><li>f= m x a </li></ul><ul><li>force = mass x acceleration </li></ul><ul><li>SI UNIT: its SI unit is ‘force’. </li></ul>
  10. 11. NEWTON’S THIRD LAW OF MOTION <ul><li>Whenever one body exerts a force on another body, the second body exerts equal and opposite force to the first body. OR, </li></ul><ul><li>To every action there is equal and opposite reaction. </li></ul><ul><li>EX: the rocket works on the principal of action and reaction. </li></ul><ul><li>When a bullet is fired from the gun, a force sending the bullet forward is equal to the force sending the gun backward. But due to high mass of the gun, it moves only a little distance backward and gives jerk. </li></ul>
  11. 12. CONSERVATION OF MOMENTUM <ul><li>When two or more bodies act upon one another, their total momentum remains constant provided no external forces are acting. </li></ul><ul><li>Momentum is neither created nor destroyed. </li></ul><ul><li>Total momentum before collision = total momentum after collision </li></ul>
  12. 13. THE END MADE BY: ASHUTOSH KUMAR CLASS:9 TH ‘C’ ARMY PUBLIC SCHOOL, RANIKHET

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