An organic compound absorbs strongly in the ir at 1687 cm-1. its 1h nmr spectrum consists of two signals, a singlet at 2.1 ppm and a multiplet centered at 7.1 ppm. its mass spectrum shows significant peaks at m/z 120, m/z 105 and m/z 77. this information is consistent with which of the following structures?

The great sandini is a 60.0-kg circus performer who is shot from a cannon (actually a spring gun). you don’t find many men of his caliber, so you him design a new gun. this new gun has a very large spring with a very small mass and a force constant of 1100 n/m that he will compress with a force of 4400 n. the inside of the gun barrel is coated with teflon, so the average friction force will be only 40.0 n during the 4.00 m he moves in the barrel. at what speed will he emerge from the end of the barrel, 2.50 m above his initial rest position?