Imagine dropping a steel ball bearing into a tall cylinder full of mineral oil. Viscous drag has a significant effect on the ball bearing's downward velocity, v(t). One family of dynamic models for this takes the form:
dv/dt = g - kv^p
where g is the acceleration of gravity and k is a constant. The size of k is related to the viscosity of the medium. When k = 0, the equation is the familiar friction-free approximation for a falling mass. The exponent p is an interesting topic for discussion: for this problem, we consider p = 1.
In this problem, we use SI units, so t is in seconds, v is in meters per second, etc. Use the international standard value g = 9.807 and assume mineral oil has viscosity parameter k = 18.
(a) Find v(t). (Assume v(0) = 0.)
(b) Let y(t) denote the distance the ball bearing has dropped at time t. (This terminology entails y(0) = 0, and y(t) > 0 for t > 0.) Find y(t).
(c) Using computer assistance as appropriate, find the time required for the ball bearing to drop 1 meter from its release point.
y(t) = 1 when t =