The function below takes a single string parameter: phone_number. phone numbers will be passed in using the format '(555)867-5309'. complete the function to return the area code (the numbers wrapped in parentheses) as a string. for example, your code should return '555' if given the phone number above. hint: you can just use slicing for this.

Explain the difference laminar and turbulent flow. explain it with the shear stress and the velocity profiles.

If a particle moves along a path such that r : (3 sin t) m and ? : 2t rad, where t is in seconds. what is the particle's acceleration in m/s in 4 seconds? a)- 16.43 b)- 16.29 c)- 15.21 d)- 13.79

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