Differential free falling bodies

[darthxepher]

(i) how you solved this problem,

An object of mass 10 kg is dropped from a great height. (a) If the object is subjected to air resistance equivalent to 10 times the instantaneous velocity, find the velocity. (b) How far does the object drop after 5 sec?

(ii) what you got as a solution,

Don't know how to start. But i know you use differential equations.

(iii) why you think that is wrong.

 

[lanedance]

try writing what the force or acceleration is at any given instant...

 

[darthxepher]

Would it be 10(dv/dt)=98-10v?

 

[lanedance]

looks ok to me, now mass drops out of the equation, as it mulitplies every term..

now you can look at solving, probably a good place for separation of variables - what do you think?