*New Mexicans for Science and Reason*

*presents*

**NMSR PUZZLES**

**Send Puzzle Answers To:**

*WebMaster Dave Thomas, *
nmsrdaveATswcp.com (Help fight SPAM! Please replace
the AT with an @

**WHEN ARE PUZZLES UPDATED?**

**Since they are tied to our hard-copy newsletter and monthly
meetings, look for Puzzle Updates, usually on the Friday before the Second
Wednesday of each Month!**

Next Puzzle Posting: September 5th (or so), 2014

**August 2014 PUZZLE - "The Physicist's Spouse"**

*Submitted by Dave Thomas*

A physicist's spouse used a wheelchair, and this was firmly hooked to latches on the van's floor during excursions. The physicist wanted to minimize accelerations and decelerations while driving, as these were uncomfortable for his passenger. As they were cruising along at 12 meters/second (~27 mph), a red light turned on at the stop bar of the next intersection, a mere six meters away.

**The August Bonus:***Assuming the physicist applied constant brake pressure during the stop, and reduced the
van's speed to zero just as it reached the stop bar, what was the time τ for the braking maneuver? And what was the
constant acceleration a _{o} required?*

- BONUS Bonus #2: Suppose the physicist used a linear deceleration rate, such that he covered the six meters in a time τ , starting at zero acceleration, and ending with zero speed, and acceleration a
_{o}at the stop bar. What is the time τ for this braking maneuver, and what is the final acceleration a_{o}? - BONUS Bonus #3: Suppose the physicist used a linear deceleration rate, such that he covered the six meters in a time τ , starting at acceleration a
_{o}, and ending with zero speed and zero acceleration at the stop bar. What is the time τ for this braking maneuver, and what is the initial acceleration a_{o}? - BONUS Bonus #4: In all three bonuses, the area under the acceleration curve from 0 to τ is the same for the two givens (6 meters to stop from an initial speed of 12 m/s). What is this area, and what does it signify?
**And, which of the three alternatives given is the best for the delicate spouse?**

**Hall of Fame (August Puzzle Solvers):**