- #1

breid040

- 9

- 1

- Homework Statement
- Find the escape energy of earth. Earth's radius is 6378km, its mass is 5.976x10^24kg, and the universal gravitational constant is 6.67x10^-11

- Relevant Equations
- vescape=Sqrt(2MG/r)

I really cannot understand where this is going wrong...

Plugging in the constants, I get

vescape=Sqrt(2(6.67x10^-11)(5.976x10^24kg)/6378).

(6.67x10^-11)(5.976x10^24kg) gives me 3.99x10^14, and multiplied by 2 gives me 7.97x10^14.

7.97x10^14/6378=1.25x10^11.

The square root of 1.25x10^11 would give 353541 m/s. I

If I divide 2MR by 6378000, then it gives me the correct answer... but this is not the radius of the earth. I genuinely am stumped. I've typed this carefully into my calculator many times. Help is greatly appreciated.

Plugging in the constants, I get

vescape=Sqrt(2(6.67x10^-11)(5.976x10^24kg)/6378).

(6.67x10^-11)(5.976x10^24kg) gives me 3.99x10^14, and multiplied by 2 gives me 7.97x10^14.

7.97x10^14/6378=1.25x10^11.

The square root of 1.25x10^11 would give 353541 m/s. I

*know*that this is not right, as the escape velocity of Earth is 11.2 km/s.If I divide 2MR by 6378000, then it gives me the correct answer... but this is not the radius of the earth. I genuinely am stumped. I've typed this carefully into my calculator many times. Help is greatly appreciated.