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MJC8719
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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. Suppose that at its closest approach, the asteroid was 71000 miles from the center of the Earth -- about a third of the distance to the Moon. (Astronomical data needed for this problem can be found on the inside back cover of the text.)
(a) Find the speed of the asteroid at closest approach, assuming its speed at infinite distance to be zero and considering only its interaction with the Earth.
2.64011 km/s
(b) Observations indicate the asteroid to have a diameter of about 2.0 km. Estimate the kinetic energy of the asteroid at closest approach, assuming it has an average density of 3.33 g/cm3. (For comparison, a 1-megaton nuclear weapon releases about 5.6 1015 J of energy.)
It is part B i am getting stuck with...
I know that density = mv and once i get the mass of the asteriod I can get the KE = .5mv^2...
So D = m/v
3.33 g/cm^3 = x/(4/3)pi r^3
My question is what units do i use here...for instance, should the 3.33 g/cm^3 be converted to meters and the 2.0km converted to meters...if so, how to i convert cm^3 to m^3...
If this is not correct, could someone please guide me on the correct units to use.
thanks so much
(a) Find the speed of the asteroid at closest approach, assuming its speed at infinite distance to be zero and considering only its interaction with the Earth.
2.64011 km/s
(b) Observations indicate the asteroid to have a diameter of about 2.0 km. Estimate the kinetic energy of the asteroid at closest approach, assuming it has an average density of 3.33 g/cm3. (For comparison, a 1-megaton nuclear weapon releases about 5.6 1015 J of energy.)
It is part B i am getting stuck with...
I know that density = mv and once i get the mass of the asteriod I can get the KE = .5mv^2...
So D = m/v
3.33 g/cm^3 = x/(4/3)pi r^3
My question is what units do i use here...for instance, should the 3.33 g/cm^3 be converted to meters and the 2.0km converted to meters...if so, how to i convert cm^3 to m^3...
If this is not correct, could someone please guide me on the correct units to use.
thanks so much