- #1

- 24

- 0

## Main Question or Discussion Point

Hi guys,

My professor showed us in class how to find the final velocity of an object as it hits the the atmosphere of earth(Rf=6.37e6) and I think he might have made a mistake. I have been trying to solve the same problem but I get different answer than the one my professor showed in class.

The Ri=6.37e6 + 10^5. Vi=0.

The way I solved it - 1/2mvf^2 −GmM/Rf=−GmM/Ri (I canceled out the m)

My answer is 695 m/s.

It seems like my professor didn't cancel out the first m and he got 435 or something around that number.

I wonder if there is a reason why he didn't cancel the first m, or rather he just forgot to do so.

Thank you so much!

My professor showed us in class how to find the final velocity of an object as it hits the the atmosphere of earth(Rf=6.37e6) and I think he might have made a mistake. I have been trying to solve the same problem but I get different answer than the one my professor showed in class.

The Ri=6.37e6 + 10^5. Vi=0.

The way I solved it - 1/2mvf^2 −GmM/Rf=−GmM/Ri (I canceled out the m)

My answer is 695 m/s.

It seems like my professor didn't cancel out the first m and he got 435 or something around that number.

I wonder if there is a reason why he didn't cancel the first m, or rather he just forgot to do so.

Thank you so much!