Physics

• Ch-1

  Force and Pressure: Force- A pull or a push acting on a Object which brings change in position of the object. ex opening or closing the door; kicking the football, drawing water from well. etc. Contact force- The force exerted on a body by a direct physical touch is known as contact force * muscular * Normal * Frictional Tension Muscular- force exerted by the body muscles force. is known as muscular ex: eating, writing walking. breathing. Normal-force which acts in perpendicular. direction and it is in upwards it is known as normal force
• ex: car at rest, bottle on a table, book on a lable Frictional force- it is an opposive or resistive force which ach in opposite direction to the applied force or it a resistence to the moment the body over the surface an another body. is 이 ex: ball stopping, walking, holding a book; a car or any. vehicle stops on the road after the application of breaks. Tension: the tightness or the strengthness of the string which ads on & a body and pulls the body in an upward di direction against gravity. Ex: A tightrope walker, pendulum.
• Pressure


  The thrust per unit area the perpendicular force acting on a surface
• Pressure


  • Units: Newton per metre² (Nm²)
  • 1 pascal or bar or atmosphere
• Pressure


  1. Force

  2. Area
• Thrust


  The force acting on an object perpendicular to the surface
• More the area of the surface

  Less is the pressure acted on it
• Less is the surface area


  More is the pressure
• Broad straps to the bag


  • Provides less pressure
• More the number of tyres to lorry

  • Less is pressure
• Cutting of vegetables


  • Use sharp side of the knife to cut
  • Sharp side will have less surface area hence more pressure is exerted
• Atmospheric pressure: Atmospheric pressure is the weight of air above us that presses down on our bodies. This pressure varies with altitude. As we move higher into the atmosphere, atmospheric pressure decreases because there are fewer molecules pressing down on us.