An undiscovered planet, many lightyears from Earth, has one moon in a periodic orbit. This moon takes 19.0 days on average to complete one nearly circular revolution around the unnamed planet. If the distance from the center of the moon to the surface of the planet is 2.390 × 105 km and the planet has a radius of 3.000 × 103 km, calculate the moon's radial acceleration.

Question

isaiah.feynman · Answer

I'm thinking centripetal acceleration because its directed along the radius toward the center. So use the formula for centripetal acceleration. $$a_{c} = \frac{ v^{2} }{r }$$We don't have velocity directly given, but we know velocity id distance/time. The distance would be the circumference of the orbit. How to find the circumference use 2 pi r. r is the centre to centre distance between the moon and the planet. We can substitute for v in that equation. |dw:1411594746075:dw|