Name: ENGR 212-Dynamics Winter 2018 Quiz #2 1/25/2018 A Rail gun is used to shoot a
projectile. The gun is set-up such that the exit is flush with the ground, and the projectile will
come out at an angle of 33 deg from the vertical. The speed of the projectile when it leaves the
exit of the gun is 850 m/s. How far away from the exit of the gun will the projectile impact the
ground Useful Relations -9.81 jm/s dr dt dv dt @g = aB + B
Solution
initial velocity of projectile = 850m/s
angle with the horizontal = 90-33=57 degrees
Time of flight of projectile = 2*850*sin57/9.81 = 145.33 seconds
horizontal component of velocity = 850*cos57=462.9m/s
Therefore, horizontal distance of projectile = 145.33*462.9=67279.5 m
Answer is 67279.5 m.
On April 25, 1953, James Watson and Francis Crick published a paper .pdf
1. On April 25, 1953, James Watson and Francis Crick published a paper describing the structure of
DNA. In the original 1-page paper, they made a mistake. What was the mistake in the paper?
Solution
In that paper, they mentioned the name of DNA as deoxyribose nucleic acid which is known as
deoxyribonucleic acid. The other mistake as they mentioned there it is impossible to make a
DNA strand with ribose sugar but in nature, it exists in the form of double stranded RNA.
