A rock with mass ?m? = 3.00 kg falls from rest in a viscous medium. The rock is acted on by a net constant downward force of 18.0 N (a combination of gravity and the buoyant force exerted by the medium) and by a fluid resistance force ?f? = kv?, where ?v? is the speed in m/s and ?k? = 2.20 N s/m (see Section 5.3). (a) Find the initial acceleration ?a?0. (b) Find the acceleration when the speed is 3.00 m/s. (c) Find the speed when the acceleration equals 0.1?a?0. (d) Find the terminal speed ?vt (e) Find the coordinate, speed, and acceleration 2.00 s after the start of the motion. (f) Find the time required to reach a speed of 0.9 v ? t?.
h t g Week3Notes n • AverageVelocity e o v=Δx/Δt • AverageSpeed L o PathLength/Δt h t - a -- P -- Δ - - Example#1:BIKETRIP North5blocksin5minutes East3blocksin6minutes South5blocksin10minutes Findthetotalaveragespeedandtotalaveragevelocity. PathLength=5+3+5=13