Free-fall Notes
parachute
Name
Class Period
Date
(gpb Physics 303, 3:00 - 7:48)
Free-fall Objects in free-fall have
When a ball is in free-fall, during each successive time period, the ball is falling ______________________
and ______________________, so the motion of the ball is ______________________.
(9:09 - 10:44)
How are displacement and time related for falling objects?
Since displacement and time squared are directly related, we can use the formula _____________________
to calculate the displacement of objects in free-fall.
(13:59 - 15:22)
acceleration due to gravity: ______________________________________
(18:29 - 20:30)
Do the Reaction Time Lab.
(22:06-24:03)
When a ball is thrown straight up, what happens to the ball’s motion:
•
on it’s way up?
•
at the top of its flight?
•
on its way down?
A ball tossed upward:
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Problems
1.
After 1.5 s in the Scream at Fiesta Texas, a free fall ride, how fast are you going?
2.
A boy falls 1.4 m to the ground.
a. How long does the fall take?
b.
3.
How fast is he going as he hits?
A rock is thrown straight down with a velocity of 2.2 m/s. It takes 4.1 s to hit the Earth. How far does it fall?
Biplane
Name
Lab - Reaction Time
Class Period
Date
It takes a fraction of a second for brain impulses to travel from your eye to your brain and then to your fingers.
Reaction times vary from person to person. In this lab, your task will be to determine your reaction time using
only a meter stick and a small ruler (no clock or timer will be provided).
Part A: Determining Reaction Time
1. Hold a meter stick between the thumb and forefinger of your lab partner. The thumb and finger should be
held 5.0 cm apart to insure consistency. Make sure to check this distance, and don’t allow cheating!
Make the 50 cm mark on the meter stick even with your partner’s fingers. Drop the meter stick and have
your partner catch it on the way down only by closing the fingers (not by moving the arm down). Do not
announce when you are about to drop the meter stick.
2.
Measure the distance the stick fell before it was caught. Repeat twice more and get an average distance.
3.
Swap places with your partner and repeat to find your own reaction distance. Record only your data on
this sheet.
Trial #
My Reaction Distance
(cm)
My Reaction Distance
(m)
1
2
3
Average
4.
Since the object is falling, a = _________________.
Use your average d and solve for your reaction time:
_________________
5.
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Why was it necessary to record the distance in meters instead of cm?
Part B: Dollar Bill Drop
1.
Measure the length of a dollar bill (in meters). _________________
2.
Calculate how many seconds will it take the dollar bill to fall a distance equal to half its length.
Show your work.
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3.
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Could you catch the dollar bill and win the bet?
Explain.
4.
The eye-hand reaction time for the average person is 0.15 sec. How far will any object fall in that time?
Show your work.
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5.
Most people (would, would not) be able to catch the dollar bill. (Circle one.)
Explain.