Newton's Law of Gravitiation

• What does Newton's Law of Gravitation define?

  The gravitational force between two bodies
• How can the mass of a uniform sphere be treated in gravitational calculations?

  As a point mass at its center
• What does Newton's Law of Gravitation state about gravitational force?

  It is proportional to the product of masses
• What is the relationship between gravitational force and distance according to Newton's Law of Gravitation?

  It is inversely proportional to the square of separation
• How is the gravitational force expressed in equation form?

  F = $\frac{Gm_1m_2}{r^2}$
• What does the variable F represent in the gravitational force equation?

  Gravitational force between two masses
• What does G represent in the gravitational force equation?

  Newton's gravitational constant
• What do m1 and m2 represent in the gravitational force equation?

  Two point masses
• What does r represent in the gravitational force equation?

  Distance between the centers of the masses
• Why does Newton's Law of Gravitation apply to planets orbiting the Sun?

  Because their separation is much larger than their radius
• What is the 'inverse square law' in relation to gravitational force?

  Force reduces by $\frac{1}{4}$ when distance doubles
• If a mass is twice as far away, how does the gravitational force change?

  It reduces by $\frac{1}{4}$
• How do you calculate the mass of the Earth using gravitational force?

  1. Use the formula: $F =$$\frac{Gm_1m_2}{r^2}$
  2. Rearrange to find $m_2$ (mass of Earth)
  3. Substitute known values:

  • $F =$$37,000 N$
  • $m_1 =$$6500 kg$
  • $r =$$6400 km +$$2000 km =$$8400 km =$$8,400,000 m$

  
• What common mistake do students make when calculating gravitational force?

  Forgetting to add surface distance and radius
• What is the radius of the Earth used in calculations?

  6400 km