Asatellite moves in a stable circular orbit with speed vo at a distance r from the center of a planet. for this satellite to move in a stable circular orbit a distance 2r from the center of the planet, the speed of the satellite must be? ? i said that f=ma, but m doesn't matter since it's constant. so, a0=a1. a=v^2/r. so v1^2/2r = v0^2/r. i ended up with v1 = v0sqrt(2). but that's not the answer. all the multiple choice answers have sqrt's, 2's, and v0's scattered around, but none are what i have. what did i do wrong? ?

Work = force × a. work b. energy c. distance d. momentum

Samir watches a 100-minute movie on his spaceship. maria's spaceshipe flies in the same direction as samir's spaceship but she observes his move to last 125 minutes and his spaceship to be 40 m long. how long does samir observe his own spaceship to be? according to an observer on earth, planet x is stationary. maria and samir depart earth on their spaceships at the same time, each flying at 0.5c. maria flies toward planet x and samir flies in the opposite direction. according to maria, her voyage to planet x takes 9 years. how many years does marias voyage take according to samir?

In a simplified model of the human eye, the aqueous and vitreous humors and the lens all have a refractive index of 1.40, and all the refraction occurs at the cornea, whose vertex is 2.60 cm from the retina. what should be the radius of curvature of the cornea such that the image of an object 40.0 cm from the cornea’s vertex is focused on the retina?