The discovery of eris

a. was not surprising, because other kuiper belt objects approaching the size of pluto had already been discovered
b. was not surprising, because the existence of a massive "planet x" had been predicted nearly a century ago
c. was surprising due to its "backwards" orbit around the sun
d. was surprising since we thought we knew about all large objects in the solar system

16. a brave but inadequate rugby player is being pushed backward by an opposing player who is exerting a force of 800 n on him. the mass of the losing player plus equipment is 90.0 kg, and he is accelerating at 1.20m/s2 size 12{1 "." "20"" m/s" rsup { size 8{2} } } {} backward. (a) what is the force of friction between the losing player’s feet and the grass? (b) what force does the winning player exert on the ground to move forward if his mass plus equipment is 110 kg? (c) draw a sketch of the situation showing the system of interest used to solve each part. for this situation, draw a free-body diagram and write the net force equation.