An undiscovered planet, many lightyears from earth, has one moon in a periodic orbit. this moon takes 23.0 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 2.060×105 km and the planet has a radius of 4.000×103 km, calculate the moon's radial acceleration a=/s^2

Consider two less-than-desirable options. in the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. in the second option you are driving 30 mph and crash head-on into a stationary brick wall. in neither case does your car bounce off the thing it hits, and the collision time is the same in both cases. which of these two situations would result in the greatest impact force?