Math Is Fun Forum

student1

Member

Registered: 2009-04-07

Posts: 2

velocity

A 100kg object is released from rest at an altitude of h=50km. Ignoring aerodynamic drag and wind behaviour, determine the velocity of the object just before it strikes the earth at sea level, asumming gravity is 9.81 m/s^2 and constant

could anyone please help me out with this by pointing me in the right direction

thank you

luca-deltodesco

Member

Registered: 2006-05-05

Posts: 1,470

Re: velocity

you can use both constant acceleration formula and conservation of energy:

or

Last edited by luca-deltodesco (2009-04-07 02:23:08)

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bossk171

Member

Registered: 2007-07-16

Posts: 305

Re: velocity

For problems like these, I like to first write down everything I know (for example, m=100 kg, a=g=9.81 m/s^2 etc...) then write down the equations I know (like luca-deltodesco did). Usually, it's pretty obvious which equation to use after I know what variables I have.

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student1

Member

Registered: 2009-04-07

Posts: 2

Re: velocity

thank you very much!

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 49,031

Re: velocity

Since

,

Hence, the approximate velocity of the object just before it strikes the earth at sea level is 990.45 meters per second.

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mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: velocity

It's worth noting that at this kind of speed, ignoring air resistance is a pretty big assumption to make.

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