Correct A Near Miss! In the early morning hours of June 14, 2002, the Earth had
ID: 2041071 • Letter: C
Question
Correct A Near Miss! In the early morning hours of June 14, 2002, the Earth had a remarkably close encounter with an asteroid the size of a small city The previously unknown asteroid, now designated 2002 MN, remained undetected until three days after it had passed the Earth At its closest Part B approach, the asteroid was 73 600 miles from the center of the Earth-about a third of the distance to the Moon Observations indicate the asteroid to have a diameter of about 2 0 km Estimato the kinotic energy of the esteroid at closest approach assuming it has an average density of 3 30 g/euFor comparison, a t megaton nuclear weapon releases about 56 x 101hJ of energy) Express your answer to two significant figures SubmitExplanation / Answer
mass of asteorid,
m = density*volume
= 3300*(4/3)*pi*1000^3
= 1.38*10^13 kg
r1 = infinite
r2 = 73600 miles
= 74600*1609 m
= 1.20*10^8 m
Me = 5.98*10^24 kg
Apply conservation of energy
final mechanical energy = initial mechanival energy
U2 + KE2 = U1 + KE1
-G*Me*m/r2 + KE2 = -G*Me*m/r1 + 0
-G*Me*m/r2 + KE2 = 0 + 0 (since r1 = infinite)
KE2 = G*Me*m/r2
= 6.67*10^-11*5.98*10^24*1.38*10^13/(1.20*10^8)
= 4.60*10^19 J <<<<<<<-------Answer