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Kinematics and variable acceleration question

An object falls through a fluid so that the distance fallen, in metres, at time t seconds is given by s=40(4e^(-t/4) + t - 4). Find the initial and terminal speeds of the object.
I am a bit stuck with the terminal speed please help??:confused:
Thanks in advance!
Original post by firsedge
An object falls through a fluid so that the distance fallen, in metres, at time t seconds is given by s=40(4e^(-t/4) + t - 4). Find the initial and terminal speeds of the object.
I am a bit stuck with the terminal speed please help??:confused:
Thanks in advance!


Initial speed will be when t=0.
Terminal speed is the limiting value as t tends to infinity.
Reply 2
Original post by firsedge
An object falls through a fluid so that the distance fallen, in metres, at time t seconds is given by s=40(4e^(-t/4) + t - 4). Find the initial and terminal speeds of the object.
I am a bit stuck with the terminal speed please help??:confused:
Thanks in advance!

v=dsdtv=\dfrac{ds}{dt}
Find the value of that when t goes to infinity
Original post by firsedge
An object falls through a fluid so that the distance fallen, in metres, at time t seconds is given by s=40(4e^(-t/4) + t - 4). Find the initial and terminal speeds of the object.
I am a bit stuck with the terminal speed please help??:confused:
Thanks in advance!


the speed is the derivative of distance w.r.t. time.

So differentiate the function to get ds/dt (which is speed). Then look at what happens when you let t go to infinity (that's the terminal speed, ie the speed it reaches when time tends to infinity)
Reply 4
Thats great thanks guys!

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