How far is the center of mass from the handle end of the club-axe?

In summary, the club-axe consists of an 11.0 kg stone attached to the end of a 2.9 kg stick. The center of mass is at 87.26 cm from the handle end, as calculated by balancing the weight of the stone and the stick.
  • #1
bkhofmann
17
0

Homework Statement



A club-axe consists of a symmetrical 11.0 kg stone attached to the end of a uniform 2.9 kg stick, as shown in the figure. The length of the handle is L1 = 93.0 cm and the length of the stone is L2 = 10.0 cm. How far is the center of mass from the handle end of the club-axe?

Homework Equations





3. The Attempt at a Solution [/b
I'm not sure how to do this, I can up with 58.9cm on my own but most likely not the correct way, any help appreciated!
 
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  • #2
bkhofmann said:

Homework Statement



A club-axe consists of a symmetrical 11.0 kg stone attached to the end of a uniform 2.9 kg stick, as shown in the figure. The length of the handle is L1 = 93.0 cm and the length of the stone is L2 = 10.0 cm. How far is the center of mass from the handle end of the club-axe?

Homework Equations



3. The Attempt at a Solution [/b
I'm not sure how to do this, I can up with 58.9cm on my own but most likely not the correct way, any help appreciated!


How much do they weigh together?
Won't half the weight be on each side at the balance point?

Starting from the end with the stone, how much does the weight of the stone increase the weight to it's side of the balance point on a per cm basis? If the stick passes through the stone, how much does the stick add per cm? Now all you have to do is divide that into half the total weight to give you where it balances.
 
  • #3
I believe that's what I have done. Do you come up with 58.9 cm?
 
  • #4
bkhofmann said:
I believe that's what I have done. Do you come up with 58.9 cm?

How is that answer possible?

The balance point must lie within the stone as it is 4 times heavier than the whole stick.
 
  • #5
Ok the stone weighs 1.1kg/cm and the stick is 1.1 kg/35.279cm. Is this what you are talking about?
 
  • #6
bkhofmann said:
Ok the stone weighs 1.1kg/cm and the stick is 1.1 kg/35.279cm. Is this what you are talking about?

So no, you should deal with the center of mass of the stone.

Where is the stone? Added to the end? Or is the stick through the middle?
 
Last edited:
  • #7
I got it (46.5x2.9+98x11)/(2.9+11), the stone is just added on.
 
  • #8
bkhofmann said:
I got it (46.5x2.9+98x11)/(2.9+11), the stone is just added on.

OK. Sorry, my first post was a little misleading.

What you are balancing then is something on the left (the stone end) that looks like

1.1*(10 - x)/2 the center of mass times the moment arm that equals
1.1*x/2 +2.9*(x+46.5)

So the total from the handle end is 93 + x.
 
  • #9
the center of mass is at 87.26cm from the end of the stick and lon-capa accepted it.
 
  • #10
bkhofmann said:
the center of mass is at 87.26cm from the end of the stick and lon-capa accepted it.

OK. So the stick goes to the end of the stone. Not the stone at the end of the stick.

Sounds about right then.
 

Related to How far is the center of mass from the handle end of the club-axe?

1. What is the definition of center of mass?

The center of mass is the point in an object where all the mass is evenly distributed around it, making it the balance point of the object.

2. How is the center of mass calculated?

The center of mass is calculated by taking the sum of the products of each individual mass and its corresponding distance from a chosen reference point, divided by the total mass of the object.

3. Why is it important to know the location of the center of mass?

Knowing the location of the center of mass is important because it helps determine the stability and balance of an object. It also helps in predicting the motion of an object and understanding how external forces will affect it.

4. How does the location of the center of mass affect the handling of a club-axe?

The location of the center of mass affects the handling of a club-axe by determining the point where the axe will pivot or rotate when swung. If the center of mass is closer to the handle end, it will be easier to control and swing the axe. If it is closer to the blade end, the axe may feel heavier and more difficult to control.

5. Can the location of the center of mass be changed?

Yes, the location of the center of mass can be changed by altering the distribution of mass in the object. For a club-axe, this could be done by adding weight to one end or removing weight from another, thereby shifting the center of mass closer to one end or the other.

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