Question 1.1
Chevy is fast!How about BMW?NJIT Physics 1: Distance, time and
how we measure them are basic to understanding motion.
2015 Chevy Corvette Z06
2015 BMW M1 Concept Car
How fast did my Chevy go in m/s?I was travelling in a fast Chevy
in the desert. I timed the car going 4 miles in a minute, but my
accuracy was only about 2% in each measurement because I used a
mile marker and a hand timer. I told a friend from Europe, and she
said it was no big deal. She had gone 100m/s in her much faster
BMW. In her standard units what was my Chevys speed?
Carcabin.com
Step by step solution:Sketch
Convert x and t to standard units: 3. Write the physics
equation:Do the math: Estimate the uncertainty: Comment on the
numbers:60sec=1min1609m=1mi2.24mi/hr=1m/s
Use the step by step methodTo answer the questionStep by step
solution:Sketch
2. Convert x and t units:
x=4mi*[1609m/1mi]=6436mt=1.0min*[60sec/1min]=60s3. Physics:
v=(x-xo)/tMath: v=6436/60s=108m/sUncertainty: 2% in x; 2% in t; ~4%
in v; v is probably between 100 and 116 m/sBut not really faster
than the claim of v=100 for the BMW. Comment: The Chevys measured
speed is fast: 108m/s*[2.24mi/hr]/[1m/s]=240mi/hr!
xo=0 x=4milesto=0 t=1min
Homework:Calculate when you have to leave home in order to get
to class on time.Read the part of chap 1 on x, t, v and unitsMake a
description of your trip from home to this class in terms of x, t,
and the average v for segments of your trip where your v is roughly
constant. E.g. walking, driving in local traffic, driving on
freeways.Convert to standard unitsEstimate the uncertaintiesHand in
a written report at next class.Also figure out when you have to
leave home to get to class on time?
