Laws of Motion - Part 2

Newton's Third Law

• For every action, there is an equal and opposite reaction.

Gravitation

• The force exerted by one body on another body.

• Formula for gravitational force:

  [ F = G \frac{m_1 m_2}{r^2} ]

  • ( G ) = universal gravitational constant = 6.67 × 10^-11 N m²/kg²
  • ( m_1, m_2 ) = masses of two bodies
  • ( r ) = distance between the bodies

Characteristics of Gravitation

• If an object is thrown upwards, its velocity will increase.
• The falling object's motion will reduce.
• Due to gravity, objects change their motion.
• Acceleration of the falling object, known as "g", = 9.8 m/s²

Weight and Mass

• Mass = the amount of matter present in an object

• Weight = force exerted on an object due to gravity

  [ W = mg ]

  • ( W ) = weight (N)
  • ( m ) = mass (kg)
  • ( g ) = acceleration due to gravity (m/s²)

Free Falling Body

• The motion of an object falling from a height is called "free fall."

• During free fall, the initial velocity (u) = 0.

• Formula for the height covered by the falling object:

  [ s = ut + \frac{1}{2} g t^2 ]

Numerical Questions

• Questions based on Newton's Third Law, such as:
  1. If a force of 10 Newton is applied in the east direction, the reaction force on the wall will be 10 Newton in the west direction.
  2. Solving questions by using the formula for weight ( W = mg ).

Important Formulas

1. [ F = G \frac{m_1 m_2}{r^2} ]
2. [ W = mg ]
3. [ s = ut + \frac{1}{2} g t^2 ]

Conclusion

• Studying the laws of gravitation and motion is important.
• Newton's Laws can be observed in daily life.

Suggestions for Study

• Understanding future questions for upcoming chapters.
• Regularly updating your notes.
• Remembering important formulas and practicing questions.

Note: These notes are for study purposes only.