Force and Pressure Class 8 ICSE Physics | Selina Chapter 3 | Turning Effect of Force #1

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Force is described as a push or pull that changes an object's state, affecting its motion, shape, or size. The chapter explores various examples of force application, the unit of Newtons, and the concept of turning effect, emphasizing the importance of perpendicular distance for efficient force application in different scenarios.

Insights

  • Force, defined as a push or pull, can change an object's state by initiating movement, altering shape, or adjusting size, but it cannot affect an object's mass.
  • The turning effect of force, influenced by magnitude and perpendicular distance, allows for easier rotation of objects around a pivot, demonstrated in various activities like door opening, flour grinding, pottery making, and drilling, emphasizing the significance of distance in reducing the required force.

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Recent questions

  • What is force in physics?

    Force is a push or pull that changes an object's state, such as motion, rest, shape, or size.

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Summary

00:00

Force and Pressure in Class A Physics

  • The chapter being discussed is Force and Pressure in Class A Physics.
  • Force is defined as push or pull that changes the state of an object, either bringing it to rest, into motion, or altering its shape or size.
  • Force applied to an object at rest causes it to start moving, exemplified by a car or a ball being kicked.
  • Swinging on a swing involves applying force to change its motion, speed, or direction.
  • Force can change the shape and size of objects, demonstrated by squeezing toothpaste or stretching a rubber band.
  • Force cannot change the mass of an object, and it is felt through its effects on movement, stationarity, shape, or size.
  • Force is expressed by magnitude and direction, represented by an arrow where the length indicates magnitude.
  • The unit of force is the Newton, named after Isaac Newton, defined as the force that increases the speed of a 1kg object by 1 meter per second.
  • Gravity exerts a force of 1kgf on a 1kg mass, equivalent to 9.8 Newtons.
  • The turning effect of force occurs when a force applied to a non-free-moving object causes it to rotate around a pivot or axis, influenced by magnitude and perpendicular distance from the pivot.

18:47

Leverage: Maximizing Distance for Easy Rotation

  • The greater the perpendicular distance between the axis of rotation and the point of force applied, the easier it is to open or close doors or any pivoting object, requiring less force.
  • Hand grinding flour involves rotating a stone by placing a handle at a maximum distance for easy rotation, applying the same principle as in door opening.
  • Turning a potter's wheel involves placing a stick at a maximum distance from the center pivot to rotate the wheel with less force, aiding in pottery making.
  • Turning a drill machine requires a longer perpendicular distance from the force application point to the pivot for efficient drilling, similar to steering wheels and bicycle pedals.
  • Using a spanner or screwdriver with long handles reduces the force needed to rotate nuts or screws by increasing the perpendicular distance between the force application point and the pivot.
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