Question

Saturn’s moon Titan has a mass of 1.35 × 1023 kg. If Titan is 1.19 × 106 km from Saturn, and Saturn’s mass is 5.86 × 1026 kg, what is the gravitational force between Saturn and its moon?

2.76 × 104 N
3.29 × 107 N
3.73 × 1021 N
4.43 × 1030 N

Answer 1

Use Newton's law of gravitation: F = G M m / r^2.

Convert distance: 1.19 × 10^6 km = 1.19 × 10^9 m.

Compute:
F = (6.674×10^−11 N·m^2/kg^2)(5.86×10^26 kg)(1.35×10^23 kg) / (1.19×10^9 m)^2
≈ 3.73 × 10^21 N.

Answer: 3.73 × 10^21 N.