Equillibrium & center of mass

Equillibrium & center of mass
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NatuurkundeMiddelbare schoolvmbo lwooLeerjaar 2,3

This lesson contains 38 slides, with interactive quizzes, text slides and 5 videos.

time-iconLesson duration is: 1 min

Items in this lesson

Equillibrium & center of mass

Slide 1 - Slide

You know how to determine the center of mass
You can explain the difference between stability and equillibrium
You can explain what to do to make something more stable

Slide 3 - Slide

Slide 4 - Slide

Slide 5 - Slide

Slide 6 - Slide

0

Slide 7 - Video

Slide 8 - Video

Equillibrium

Slide 9 - Mind map

How is this possible?

Slide 10 - Slide

How is this possible?


Can you try to explain the bird balancing on your finger?

Slide 11 - Open question

How is this possible?

Slide 12 - Slide

How is this possible?


Can you try to explain why this construction 
does not fall to the ground?

Slide 13 - Open question

Center of mass
Every object has a center of mass. 

If the point of application of a force originates in the center of mass of an object, the object will follow a linear acceleration without an angular acceleration.


Slide 14 - Slide

Slide 15 - Slide

Stability
An object could be in a state of equillibrium even if it is unstable.

A state of equillibrium is reached when all forces and moments equal each other out.

If an object is stable or unstable depends on how easy it is for the center of mass to get outside of the support area.

The higer the center of mass is situated and the smaller the support area, the more unstable an object will be.

Slide 16 - Slide

Drag to the corresponding red box
MOST STABLE
in between
LEAST STABLE
A
B
C

Slide 17 - Drag question

Drag to the corresponding red box
EQUILLIBRIUM
NO EQUILLIBRIUM
A
B
C

Slide 18 - Drag question

Slide 19 - Slide

Slide 20 - Slide

Slide 21 - Slide

So tell me

What do you need for a stable equillibrium?

Slide 22 - Open question

Equillibrium 1
When all forces equal each other out.
The resultant force (also called netforce) = 0 N


The object will be in rest.

It either wil not move, or only move with a constant speed.
It wil not start to change its speed, direction or shape

Slide 23 - Slide

Equillibrium 2


In both situations there is an equillibrium.

As you can see all forces equal each other out, 
since both boys have the same mass and are 
sitting at the same distance from the middle.

Slide 24 - Slide

Equillibrium 3
There are situations possible in which there  is no 
equillibrium even though all forces equal each other out.

To have an equilibrium, not only all forces need to cancel
each other out, the rotational effects need to cancel 
each other out as well.


Equillibrium
Only when:

all forces canceleach oher out:
the resultant force =  0 N

And

all moments (the clockwise and anti clockwise rotational effect) 
cancel each other out. The resultant moment = 0 Nm

Slide 25 - Slide

Equillibrium

  1. Resultant force is zero  
  2. Resultant moment is zero
keep in mind 
that:
stability is not the same as equillibrium
  1. Low center of mass
  2. Large support area
  3. Large mass
Stability

Slide 26 - Slide

Slide 27 - Video

Slide 28 - Video

Slide 29 - Video

Slide 30 - Slide

Which object is more stable?
A
A
B
B

Slide 31 - Quiz

Three cans of coke.
The first is full.
The second has been emptied halfway.
The third is totally empty.
Which can is the most stable?

Slide 32 - Open question

Challenge: Can you balance a can of coke on its side.

Make a photo if you succeeded.

Slide 33 - Open question

An object tumbled over

Can you mention some causes?

Slide 34 - Open question

Using that what you have just learned, can you explain why the Fosbury Flop makes you jump higher than before?

Slide 35 - Open question

Slide 36 - Slide

Slide 37 - Slide

Slide 38 - Slide