A person pushes a block of mass m on a surface. Here, the friction force is defined as a function of velocity: Fk = −kv ∙ v = −kv ∙ dx dt

(1)Set up an equation of motion for the system above, i. e., differential equation for x(t):
(2)Solve the differential equation and obtain x(t). Here, F(t) = 0.

For the closed feedwater heater below, feedwater enters state 3 at a pressure of 2000 psia and temperature of 420 °f at a rate of ix10 ibhr. the feedwat extracted steam enters state 1 at a pressure of 1000 psia and enthalpy of 1500 btu/lbm. the extracted er leaves at an enthalpy of 528.7 btu/lbm steam leaves as a saturated liquid. (16) a) determine the mass flow rate of the extraction steam used to heat the feedwater (10) b) determine the terminal temperature difference of the closed feedwater heater