Saturday
September 20, 2014

Homework Help: Physics/Math

Posted by Technoboi11 on Monday, March 12, 2007 at 12:17am.

Ok...I figured out part a but I am having trouble with b. part a was:
Zero, a hypothetical planet, has a mass of 1.0x10^23 kg, a radius of 3.0x10^6 m, and no atmosphere. A 10 kg space probe is to be launched vertically from its surface.
(a) If the probe is launched with an initial kinetic energy of 5.0x10^7 J, what will be its kinetic energy when it is 4.0x10^6 m from the center of Zero?
>>>>>>>>>>>>>>>>>>
so I did KE + U = constant,
V = sqrt(2GM/R)
V = sqrt(2(6.67e-11)(1.0e23)/(3.0e6))
V = 2108.7
(1/2) mV^2 - GMm/R = constant
(.5(10)(2108.7)^2 - ((6.67e-11)(1.0e23)(10)/(4.0e6))
111165392.3 - 16675000 = 94490392.3 = 9.4e7=constant
9.4e7-5e7=4.4e7 J which is the right answer...but for b:
>>>>>>>>>>>>>>>>>>>>>>
If the probe is to achieve a maximum distance of 8.0x10^6 m from the center of Zero, with what initial kinetic energy must it be launched from the surface of Zero?
->I am not sure what to do. I recalculated the constant using the radius of 8e6 m and got 2.78e6 J but then I am not sure what to use for U. U=mgd so I tried U=(10)(9.8)(3e6) and subtracted that from 2.78e6 J but that is wrong. What am I missing?

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

Physics/Math - Ok...I figured out part a but I am having trouble with b. part a ...
Physics - Zero, a hypothetical planet, has a mass of 1.0x10^23 kg, a radius of 3...
Re: Physics/Math - Posted by Technoboi11 on Wednesday, March 7, 2007 at 1:09am. ...
chemistry - if the combustion of oil yields 4.0x10^4 kj/kg what mass of oil must...
chemistry - if the combustion of oil yields 4.0x10^4 kj/kg what mass of oil must...
Physics - Astronomers can calculate the mass of a planet by using the orbital ...
College Physics - Some bacteria are propelled by motors that spin hair-like ...
chemistry 12 - hey i was wondering, i have this question: Sketch a pH curve for ...
Chemistry - what is Kc at 25 celsius for the following equilibrium? CH3BH3^+ +...
physics - The acceleration due to gravity near a planet's surface is known to be...

Search
Members