1. PHYS16 – Lecture 5 Free Fall and Race Cars: Constant Acceleration September 17, 2010 Too Good to be True??? Lingenfelter Corvette http://Z06-corvette.com

2. Administration Key Concepts – Physics 1D motion Constant Acceleration Agenda

3. Homework Assignments – Due Sunday, Written homework, Math Exam, & Ch. 3 Online homework Administration

4. Key Concepts: Physics 1D Motion Displacement, Velocity, & Acceleration – Know the definitions of these terms – Know how they are related Motion with Constant Acceleration – Solve for constant accel. get Kinematic Eqs. – Use the Kinematic Eqs. to solve problems Free Fall Race Car

5. What is constant acceleration? Acceleration = constant (0 or some #) Velocity can be approximated as linear How many of these things have a=const? – Trains – People – Planes – Cheetahs – Automobiles Examples of a ≠ constant? Bee flying Dust Particle in the wind

6. Derive Kinematic Equations for Constant Acceleration

7. Last time XVAXVA

8. Derive Kinematic Equations

9. Free Fall

10. Free Fall – Using the Equations Constant acceleration is due to gravity Drop a ball from 3 m, how long does it take to hit the ground?

11. Free Fall – What does it imply? Demo: Falling Balls Demo: Feather vs. Penny http://panda.unm.edu/demos

12. Free Fall – What does it imply? Acceleration of any size or mass object should be the same – Penny should fall at the same rate as feather – This isn’t true due to air resistance – In vacuum it is true!

13. Race Cars

14. Lingenfelter Corvette Can it really do 0 to 60 mph in 1.97 s? Let’s calculate some #’s to see if it is reasonable http://Z06-corvette.com

15. Lingenfelter – 0 to 60 mph in 1.97 s

16. Stock Car – 0 to 333. 2 mph in ¼ mile

17. C6 Corvette – 0 to 60 mph in 4.2 s

18. Is it true? Stock Car – 220,000 miles/hr 2 Lingenfelter Corvette – 110,000 miles/hr 2 C6 Corvette – 51,000 miles/hr 2 Yes, let’s look at some data from youtube…

19. Summary Most physical objects experience constant acceleration Use Kinematic equations of Motion to solve for problems with constant acceleration Examples: Free Fall and Race Car