Question

(a) find the magnitude of the gravitational force between a planet with mass 7.50 3 1024 kg and its moon, with mass 2.70 3 1022 kg, if the average distance between their centers is 2.80 3 108 m. (b) what is the acceleration of the moon towards the planet? (c) what is the acceleration of the planet towards the moon?

Answer 1

The magnitude of the gravitational force between two bodies is the product of their masses divided by the square of the distance between them. So we have F = M1*M2 / r^2. M1 = 7.503 * 10e24 and M2 = 2.703 * 10e22 and r= 2.803 * 10e8; r^2 = 5.606 *10e16. So we have 7.503 *2.703 *10^(24+22) = 20.280 * 10^(46). Then we divide our answer by 5.606 * 10e16 which is the distance ; then we have 3.6175 * 10 e (46- 16) = 3.6175 * 10e30. To find the acceleration we use Newton's second law F = ma. F is 3.6175 * 10e30 and M is 7.503 * 10e24 so a = F/M and then we have 3.6175/7.503 * 10e (30-24) = 0.48 * 10e6. Similarly for moon, we have a = 3.6715/2.703 * 10e(30-22). = 1.358 * 10e8