Question

3. 1 AU = 149 597 970 700 metres, and the Sun’s mass is 1.98855 x 1030 kg. (a) Calculate the apparent tidal force on the two rocks from question 2 due to the Sun, and (b) use your results from questions 2 and 3 to give a qualitative explanation of the difference between spring tides and neap tides. Note: You will have to be careful about significant figures; take the 1-kg mass as an absolute value.

Q2 Results

2. The average distance from the Moon to the center of the Earth is 384,400 km, and the diameter of the Earth is 12,756 km. Calculate the gravitational force that the Moon exerts

(a) on a 1-kg rock at the point on the Earth’s surface closest to the Moon = 3.5 x 10 ^ -5 N

(b) on a 1-kg rock at a point on the Earth’s surface furthest from the Moon. The mass of the Moon is 7.349 × 1022 kg. = 3.2 x 10 ^ -5 N

(c) Find the difference between these two forces. This difference is the apparent tidal force from the Moon pulling the two rocks apart. = 0.3 x 10 ^ -5 N

Answer 1