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Most geologists believe that the dinosaurs became extinct 65 million years ago when a large comet or asteroid struck the earth, throwing up so much dust that the sun was blocked out for a period of many months. Suppose an asteroid with a diameter of 2.0 km and a mass of1.0×1013kghits the earth (6.0×1024kg)with an impact speed of 4.0×104m/s.

a. What is the earth’s recoil speed after such a collision? (Use a reference frame in which the earth was initially at rest.)

b. What percentage is this of the earth’s speed around the sun? The earth orbits the sun at a distance of1.5×1011m.

Short Answer

Expert verified

Part (a). The earth’s recoil speed after collision is 6.67×10-8m/s

Part (b). Percentage of the recoil speed with the speed of the earth around sun is 2.23×10-10%

Step by step solution

01

Step 1. Given Information is:Diameter of the asteroid = 2 kmMass of the asteroid = 1.0×1013kgMass of the earth = 6.0×1024kgImpact speed = 4.0×104m/sEarth orbits the sun at a distance of 1.5×1011m

We need to find out :

a) The earth’s recoil speed after collision

b) Comparison of it with earth's speed around the sun.

02

Part (a).  Step 1Using Law of conservation of Momentum.

pasteroid=pearthmasteroidvasteroid=mEarthvEarth1×1013kg4×104m/s=6×1024kgvEarthvEarth=4×1017kgm/s6×1024kg=6.67×10-8m/s

03

Part (b). Step 1Calculating earth's speed around the sun.

We know that,

v=2πTrTisthetimeperiodofeartharoundsunthatis,T=365days=365×24×3600seconds=31.536×106sPuttingvalues,Vearth-Sun=2π31.536×106×(1.5×1011m)Vearth-Sun=3×104m/sPercentageofrecoilspeedwiththespeedoftheeartharoundsunis:%=VearthVearth-Sun6.67×10-8m/s3×104m/s×100=2.23×10-10%

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