Two pairs of dancers encounter each other on the dance floor. The couples switch partners with each woman now dancing with the other man. This situation is analogous to which kind of reaction?

50 inches should be the resultant vector

the first american roller coaster was the mauch chunk switchback railway, built in the mountains of pennsylvania in the mid-1800s. the track, originally built to send coal to a railway, was reconfigured as a "scenic tour."

i believe the answer would be:

d. violin, clarinet, french horn, and tuba