Math Is Fun Forum

Identity

Member

Registered: 2007-04-18

Posts: 934

Air resistance

A body of mass m is projected vertically upwards with speed u. Air resistance is equal to k times the square of the speed where k is a constant. find the maximum height reached and the speed when next at the point of projection. Thanks

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Air resistance

By Newton’s second law,

Now

.

Solve the differential equation with the initial condition

for the first part.

For the second part, the differential equation is

which, changing variables as before, leads to

Last edited by JaneFairfax (2009-01-11 03:41:57)

Identity

Member

Registered: 2007-04-18

Posts: 934

Re: Air resistance

thanks Jane I've got it now