A particle of mass 1kg moves only in the region x>0 under the potential energy V(x)=x28+2x2 (in joules, x in metres). Its total mechanical energy is 20J. Which option correctly gives all the positive turning points of the motion?
a) A single turning point at x≈0.65m
b) Two turning points at x≈1.0m and x≈2.0m
c) Two turning points at x≈0.65m and x≈3.1m
d) A single turning point at x≈3.1m