Transcript wk12-ppt
Announcements • Common Exam 3 is ON Monday. Usual time and locations • Today’s material WILL NOT BE on the exam. • Historically, Fluid Dynamics has NOT been covered in Phys 111. You typically will NOT see examples of it on old exams. • We have class on TUESDAY next week…. Tuesday follows a THURSDAY schedule. • Due date for HW for TODAYS material is first Thursday in December. • HW 13 AND HW 14 are due Reading day. Iclicker Question #1 Why do golf balls have dimples on their surface? A) B) C) D) It is more stylish than a smooth surface The golf balls roll straighter when putting on the green The dimples reduce the air drag making the golf ball travel further The dimples increase the air drag limiting the travel distance so that golf courses do not need to be to large E) The dimples create a lifting force which makes the golf ball travel further Iclicker Question #2 What is the world record depth of a free dive (no breathing apparatus) with fins? A) B) C) D) E) 30m 50m 61m 101m 128m Iclicker Question #2 What is the world record depth of a free dive (no breathing apparatus) with fins? A) 30m B) 50m C) 72m – Nov 17th, 2013 – Brooklyn Diver died on an attempt without oxygen or fins. D) 101m – Women’s record E) 128m – Men’s record Technical Issues: (a) Pressure of water on human body compresses lungs. (b) body is oxygen deprived. Static Equilibrium F y ma 0 Pascal’s Law Manometer Archimede’s principle Eureka! Fluid exerts an upward force on a body equal to the weight of the fluid displaced by the body Iclicker Question #2 Which statement is true regarding the pressures and velocities of a liquid flowing in the tube below? A) The pressures at point 1 and point 2 are equal. B) The velocities at point 1 and point 2 are equal. C) The velocity at point 1 is larger than point 2, but the pressure is smaller at point 1 compared to point 2. D) The velocity and pressure are higher at point 2 compared to point 1 E) The velocity is higher at point 2, but the pressure is lower at point 2 1 2 Flow lines and continuity equation A1v1 A2v2 Deriving Bernoulli’s Equation Iclicker Question #3 For water in an open water tank, what is the velocity of the water which escapes from the bottom? A1 H A2 2 gH A) V22 1 ( A2 / A1 ) 2 B) V22 2 gH C) V22 Patm 2 gH D) It depends on the mass density of water E) Can not be determined without knowing the velocity of water at the top of the tank Lift of airplane wing 1 1 2 2 PL VL Pu VU 2 2 Since Velocity under wing is lower than velocity above wing, pressure below must be higher then pressure above Net force = (PL-Pu) Awing Viscous flow in a pipe Laminar versus Turbulent flow Golf ball Golf Ball Trajectory Top spin on a tennis ball (or sinker ball pitch) ICLICKER What are your plans for the Summer? A) B) C) D) E) Go on vacation Take classes Get a job Do absolutely nothing I have not thought about it yet Think about a RESEARH EXPERIENCE • • • • Paid positions Looks good on a resume Experience practice application of your major Perhaps you are thinking about pursuing Master’s or PhD? Options: • National Science Foundation – Research Experience for Undergraduates (REU). Apply Now http://www.nsf.gov/crssprgm/reu/reu_search.jsp • Summer positions with local companies – Speak with your advisor or Career Services • Positions at NJIT – Do faculty in your department have NSF funding? They can get Summer REU support for you. • Provost’s Summer Research Program http://www.njit.edu/provost/events/undergrad_research.php NOTE: Contact person will be different this year. Apply in Spring Semester