These are the contents of a pamphlet that I put together for a brief introduction to some basic principles of an activity, in this case, bicycling. I plan to prepare more of these.
(Below is the title page)
DID YOU KNOW THAT YOU CAN LEARN PHYSICS WHILE RIDING YOUR BIKE?
It answers the following questions:
What
is torque?
How does pedaling cause the bike to speed up?
How does braking cause the bike to slow down?
_______________________________________________________
(This is the inside, 3 columns)
INTRODUCTION TO BIKE PHYSICS
from: www.angelfire.com
The Physics of Pedaling
The big question is: How is human power used to turn the wheels of
the bicycle to cause it to move?
Well, when riding a bike, human power
is used to turn the pedals. The pedals turn the front cog (the larger one),
which has teeth that are pulling a chain. The chain is what causes the rear cog
to turn, which turns the back wheel of the bicycle.
The physics is involved in the pedaling
itself. The lever arm is the bar
that connects the pedal to the cog. When a person places his foot on the pedal,
the force he puts on it is perpendicular to the lever arm. This produces torque.
What is Torque?
Torque is what causes rotational speed
to change.
Just as greater net forces
cause greater linear accelerations,
greater torques cause greater rotational or angular
accelerations.
Torque is composed of 2 different
things: A force and a lever arm.
The component that is perpendicular to the axis of rotation is the only component of force that produces torque.
The line of action is an extended line
drawn colinear with the force.
The lever
arm is the distance between the line of action and the axis of rotation, measured on a line that is
perpendicular to both.
Note Another way of defining torque: Torque is a twisting or turning force.
The Physics of Braking
What is the purpose of brakes? Brakes increase the amount of friction on the
wheel, allowing the rider to slow or stop. A person can use the brakes by pulling on
levers which pull cables, forcing pads against the inner rim of the wheel. These pads cause a retarding force
on the rim of the wheel, in the opposite direction that the wheel is turning.
There is one lever on each handle bar,
and each lever controls either the front or rear wheel. When bicycling, a person must be careful when
applying the brakes, because his body has inertia and it still tends to go
forward. This shifts his weight forward
onto the front wheel. So he must do more
braking with the front wheel. But if there is too much braking done on the
front wheel, the inertia will cause the person to fly over the handle bars.
Note Inertia: 1st law
of motion
________________________________________________________
(This is the back page)
Bicycling
is just one of endless ways to gain an understanding of physics and
geometry. I hope this pamphlet introduces
you to seeing things you never saw before – or wondered about but just didn’t
know where to start.
Physics and geometry come into play in
every single activity and event going on around us.
Knowing how things work can add to your
performance and to your fun. So give it a try. How?
·
**Start with the
information in this pamphlet which I found
online at www.angelfire.com
· **You may not
understand everything in it right away, but for now, use what you do understand
·
**Conduct an online
search of your own
· **See what books or
videos your library has
· **Share them with your
friends, your class, your team, your scout troop
· **Read my blog and tell
others: sportscience-kathy.blogspot.com
· **See my show on Quincy
Access Television, channel 8:
“Gateway to Science:
Sports and Games”
Thank you! Kathy Hogan
Sports and games are the gateway to science,
and YOU hold the key!
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