Discover Questions

Let H=M(2x2)(for all real numbers) Is the subset
N={A in the set of H | A is not invertible} a subspace of V? Anyone can anwer this? Two forces f1 and f2 of magnitude 10√10 n each are inclined to each other at 1.8°.whats magnitude of vector f1-f2?(take π^2=10)? Benzene gives a single peak.. but how do i know it has 6 equivalent H from that single peak? How many distinguishable parts are there to the human body.?