Friday

August 1, 2014

August 1, 2014

Posted by **janie** on Monday, May 31, 2010 at 1:06pm.

(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.

(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.)

- physics -
**Damon**, Monday, May 31, 2010 at 1:29pmF = G m Me/r^2

potential energy relative to zero at infinity = -G m Me/r

here r = 84600 miles

convert that to meters

then

potential energy lost = Kinetic energy gained

G m Me/r = (1/2)m v^2

so

v^2 = 2 G Me/r

for part b you need m

diameter = 2*10^3

so

diameter/2 = radius = 1,000 meters

convert density to kg/m^3

3.33 g/cm^3 * (1kg/10^3g) * (10^6 cm^3/m^3) = 3330 kg/m^3

m = density * (4/3)pi (diameter/2)^3

then do Ke = (1/2) m v^2

- physics - reply is here for asteroid -
**Damon**, Monday, May 31, 2010 at 1:38pmThis is where I posted the reply to the multiple postings.

**Related Questions**

Physics - In the early morning hours of June 14, 2002, the Earth had a ...

physics - In the early morning hours of June 14, 2002, the Earth had a ...

physics - In the early morning hours of June 14, 2002, the Earth had a ...

physics help pleaseee - In the early morning hours of June 14, 2002, the Earth ...

physics - Evidence suggests that there are trillions of dollars' worth of ...

Physics - The asteroid belt circles the sun between the orbits of Mars and ...

physics - Consider an asteroid with a radius of 15.5 km and a mass of 3.46E+15 ...

Physics - The Earth has an angular speed of 7.272·10-5 rad/s in its rotation. ...

PHS 105 - At a particular instant, two asteroids in inter-stellar space are a ...

earth-physics - The Earth has an angular speed of 7.272 10-5 rad/s in its ...