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Course: MIT+K12 > Unit 1
Lesson 3: Physics- The physics of skydiving
- The physics of invisibility cloaks
- The science of bouncing
- How do ships float?
- Thomas Young's double slit experiment
- Newton's prism experiment
- Bridge design and destruction! (part 1)
- Bridge design and destruction! (part 2)
- Shifts in equilibrium
- The Marangoni effect: How to make a soap propelled boat!
- The invention of the battery
- The forces on an airplane
- Bouncing droplets: Superhydrophobic and superhydrophilic surfaces
- A crash course on indoor flying robots
- Heat transfer
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Shifts in equilibrium
Equilibrium occurs when the overall state of a system is constant. Equilibrium can be static (nothing in the system is changing), or dynamic (little parts of the system are changing, but overall the state isn't changing). In my video, I'll demonstrate systems in both types of equilibrium, and how the equilibrium states can be shifted. License: Creative Commons BY-NC-SA More information at http://k12videos.mit.edu/terms-conditions. Created by MIT+K12.
Want to join the conversation?
- Is their a formula for this?(3 votes)
- Why does a coin stop spinning after it has been spun?(2 votes)
- Because it is being acted on by friction, the force that opposes motion.(2 votes)
- what is meant by static equilibrium in physics(2 votes)
- Equilibrium where everything moves into a stable, non moving equilibrium. The balls in this video rolled around the tarp until resting still at the lowest point.(2 votes)
- Is there any object which is at rest but not in equilibrium?(2 votes)
- At2:57what will happen if 3 people start to spin the coin and the table is changed?(2 votes)
- how is the number -1/12 important in physics?(2 votes)
- Try watching this: https://www.youtube.com/watch?v=0Oazb7IWzbA(1 vote)
- Can a force be thought without a unit?(1 vote)
- Can it become probability for tossing a coin?Why?(1 vote)
- Why does a coin stop spinning after it has been spun?(1 vote)
- the force of gravity basically overcomes the the mass of the coin causing into to fall or in this case stop spinning.(1 vote)
- Why does a coin not move along with the pencil when you keep it on a pencil and hit the pencil?(1 vote)
- inertia, objects tend to stay in their original state until and unless an external force is applied on it.
for example when we move in a bus and it stops suddenly we tend to move forward that is your upper body still wants to move forward while your lower body remains there because it is attached to the surface of the bus.
in your example the coin wants to stay in the position of rest but when you apply force on pencil i.e. change its initial state the coin falls of it and not move with it
same principle can be applied with this simple experiment,
take a book and put your pen on it and then move the book suddenly, off coarse the pen would fall.
i pretty much expect that you would have understood the point and if not then try going to wikipedia(1 vote)
Video transcript
[MACHINE WHIRRING] Equilibrium is a balanced state. It stays balanced unless
something knocks it out of balance. [CLINK] Sometimes, it's pretty
clear that you're watching a movie in reverse. But we can tell now that time is
back to normal, driving systems into equilibrium. "Equilibrium" comes
from Latin words for "equal" and "balance." At equilibrium, opposing
forces are equal, balance each other out, and
guarantee that these balls will stay where they are. Almost anywhere I
throw the balls, they settle into this
one lowest valley, and they won't
escape the valley. Gravity is pulling
them down to the point with the lowest
potential energy. At high points, they will
high potential energy from gravity and
will use this energy to move towards the
lower energy valleys. It's the lowest valley,
but it's not the only place the balls might settle. Some balls never make
it to the lowest point. Instead, they settle
in a different valley-- in this corner. What's so special
about these places? Each of these valleys
is a stable equilibrium. Now, I'll attempt to change
where the balls land. I'll shift the landscape, which
will change the equilibrium. There's a new lowest point,
and the old lowest point is one of the
highest points now. In this new
configuration, they settle in a different equilibrium. I've successfully shifted
where the equilibrium lies. This type of equilibrium,
where nothing moves, is a static equilibrium. All of the parts of the
system are motionless, static; and the forces are
balanced, in equilibrium. But sometimes, even
when opposing forces balance each other, small
parts of the system still move. In dynamic equilibrium,
the state of the system is the average of its parts. The average state
can stay the same, even if small parts change. For example, an
individual coin can either be up and spinning or down. The state of the system
is how many coins are up. I can spin coins so that three
coins are spinning at once. As soon as I spin
up another one, friction knocks down one of the
ones that was already spinning. So even though individual
coins are changing, from spinning to not spinning
or from not spinning spinning, the overall state of the
system-- how many coins are up, 3-- stays the same. That's why we call
it "equilibrium." How do I shift this
kind of equilibrium? I can either change the rate
that the table slows them down or change the rate
that I spin them up. I enlisted my sister's
help because together we can spin coins up at a
faster rate than me alone. It turns out that together
we can spin fast enough for a dynamic equilibrium of
about five coins up at a time. We've successfully shifted
the equilibrium of the system. So how is this actually working? My sister, Claire, and
I can spin coins up faster than I could alone. To balance this, friction needs
to knock coins down faster, too. This happens when friction
has more spinning coins on the table to knock down,
so the new equilibrium happens when there are five
coins up and the rest are down. At five coins up,
Claire and I can spin up a coin at the same rate
that it takes friction to knock one down. So we're left at a stable
dynamic equilibrium of five coins up. As time runs forward, we're
driven towards equilibrium where opposing
forces are balanced and opposing rates
are equal, where we can shift where
the equilibrium lie either by adjusting the rates at
which individual objects switch state or by changing
the landscape.