8/6/2019 The Motorcyclist
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The Motorcyclist
According to Newton's first law, an object in motion continues
in motion with the same speed and in the same
direction unless acted upon by an unbalanced force. It is the
natural tendency of objects to keep on doing what they
are doing. All objects resist changes in their state of motion.
In the absence of an unbalanced force, an object in
motion will maintain this state of motion. This is often called
the law of inertia.
The law of inertia is most commonly experienced when riding on
the roadways. In fact, the tendency of moving
objects to continue in motion is a common cause of a variety of
transportation injuries - of both small and large
magnitudes. Consider for instance the unfortunate collision of a
motorcycle with a wall (or any obstacle in ints path).
Upon contact with the wall, an unbalanced force acts upon the
motorcycle to abruptly decelerate it to rest. The rider
of the motorcycle would also be decelerated to rest if strapped
to the motorcycle by seat belts or some form of safety
harness (which is not necessarily a good idea - please read
on!). Being strapped tightly to the motorcycle, the driver
would always share the same state of motion as the motorcycle.
As the motorcycle accelerates, the rider accelerates
with it. As the motorcycle decelerates, the rider decelerates
with it. And as the motorcycle maintains a constant
speed, the driver maintains a constant speed as well.
But what would happen if the rider were not wearing the seat
belt? What motion would the rider undergo if she/he
failed to use a seat belt and the motorcycle were brought to a
sudden and abrupt halt by a collision with a wall or any
other obstacle in its path? Were this scenario to occur, the
driver would no longer share the same state of motion asthe
motorcycle. If a seat belt were used on a motorcycle, then the
forces necessary for accelerated and decelerated
motion would exist. Without a seat belt, the rider is more
likely to maintain its state of motion. The animation below
depicts this scenario.
If the motorcycle were to abruptly stop, then the rider in
motion would continue in motion. The rider would likely be
propelled from the motorcycle and be hurled into the air. Once
they leave the motorcycle, the rider becomes a
projectile and continues in projectile-like motion.
But why then are motorcycles not equipped with safety harnesses?
Is this a gross oversight made by motorcycle
manufacturers? Absolutely not! While no transportation accident
is safe, it is the goal of the manufacturers of all
roadway vehicles to produce a vehicle which maximizes the safety
of its riders. In the case of a motorcycle, it is
believed that the rider's safety is maximized by not strapping
the rider to the motorcycle. In a car accident, the safest
place to be is in the car; yet in a motorcycle accident, the
worst place to be is on the motorcycle. The reason? Cars
are four-wheeled vehicles which have a stable platform capable
of resisting sideways motion and resisting tipping
over. As such, being strapped to the a car in an accident is an
advantageous strategy for maximizing passenger
safety. On the other hand, a motorcycle is a single-track
vehicle (two wheels) which are prone to tipping over and
sliding into and underneath the obstacles which they hit.
Imagine being strapped to your motorcycle as you slide
underneath a 2000-pound car. Being strapped to the motorcycle by
a safety harness, you would share the fate of the
motorcycle itself - being crushed by the 2000-pound car. Your
chance of survival would be minimal. On the other
hand, if you were to leave the motorcycle and be flung into the
air, it is more likely that your hopeful impact with the
ground would slowly alter your velocity as you skid to a stop
over a lengthened period of time. Motorcycles are
