CENTRE OF MASSIB MYP Year 4

Physics

THE LECTURE VIDEO [COM] The Centre of Mass [COM] is a point in which the entire mass of the object

is concentrated.

If a FORCE acts on the COM of the object, it will more likely accelerate in the direction of the force. [Recall the Newton’s 2nd Law of Motion]

If a force is applied on a point in the object other than the COM, the object will ROTATE/TURN about the COM itself.

If an object has a uniform density, the COM lies in the GEOMETRIC CENTRE of that object.

If an object’s density is not uniformly distributed, you would need to determine it by special methods.

ACTIVITIES TODAY [COM] The class will be divided into 4 groups.

Your Group Number will be your WORKSHEET NUMBER.

You have to ensure that the TASK assigned to you [through the worksheet] is done within 30 minutes.

SHARING of learning experiences shall follow after the activity. [You’ll be assessed by classmates on this]

Exit Pass [?]

GROUP 1 [THE MAGIC TRICK]

We believe that the centre of mass of the system is at ____________________________. We say this for the reason that ____________________________________. 

Based from how we balanced the system, we can say that objects can be balanced when the centre of mass is placed ______________________________.

GROUP 2 [THE CHAIR TRICKS]

Based from the observations while doing the activities, we can say that people balance their body by placing the centre of mass _________________________.

If the centre of mass is not above and within our feet, then we will __________________________________.

GROUP 3 [THE F-15 BALANCING]

Compare the marks in the three activities you did. What do you call this point? ____________________________________. 

Based from the observations during the activities, we can say that object can be balanced by ________________________.

The centre of mass of an object can be determined in many ways. Examples of which are ________________________.

GROUP 4 [YOU AGAINST THE WALL]

Based from the result/experiences from the activities, we can say that people balance their body by placing the centre of mass ________________________________________________.

If the centre of mass is not above and within our feet, then we will ________________________________________________. 

ESSENTIAL CONCEPTS We can think of the COM as the point where GRAVITY acts on any object.

Thus, if the PIVOT POINT [or base] does not lie directly above or below it, there will be a TURNING EFFECT.

Methods to balance objects is simply locating the COM and support it with anything like our finger, fulcrum, etc..

We can also determine the COM using a PLUM BOB. The intersection of the lines [strings] is where the COM is.

You will not be able to balance yourself if your COM lies beyond the base [on your feet]. Same goes to any other object, i.e. they will be able to stand only if the COM lies BELOW or ABOVE and within the base.

THE LEANING TOWER OF PISA

ONE MORE CHAIR CHALLENGE

EXIT PASS/FLIP CLASSROOM VIDEO Change

Transformation

Balanced

Centre of Mass

Stability

Gravity

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