A nonrotating spherical planet with no atmosphere has mass M and radius R. A projectile of mass m is launched radially from the surface of the planet with initial speed . The potential energy of the projectile-planet system, as a function of the projectile’s distance r from the center of the planet, is given by . The greatest distance from the center of the planet that the projectile reaches is A) infinity
B) R
C) 7/5 R
D) 4/3 R
E) R

I know the answer is D, 4/3 R, but I'm not sure how to get to that answer.

Imagine that you have two balloons (or, better yet, actually inflate two balloons, if possible). create static electricity around one of the balloons by rubbing it against your hair or your sweater and then bring that balloon close to the other balloon, which has not been charged. try this with at least one other object—and for variety in the discussion, avoid using an object already described by your classmates. then, for your initial post to the discussion, answer the following questions: what happened with the two balloons?

Apotter's wheel moves uniformly from rest to an angular speed of 0.20 rev/s in 32.0 s. (a) find its angular acceleration in radians per second per second. rad/s2 (b) would doubling the angular acceleration during the given period have doubled final angular speed?

What structural formula represents 4 electrons shared between two atoms?