Amazing fact: Can this Container Move?

Forums: Science And Math
Email this Topic • Print this Page

Can this container move?

You cannot apply any external force.

STAGE 1: Static Container with Center of Mass on Left Side as MOST of the mass is accumulated on Left

Code:

				

					.---------------------.

					|o                    |

					|oo                   |

					|ooo     _            |  

					|ooo    (ö)<------------Chimp throws balls in other sac 

		Ctr-Mass-->#00   /|\           |

					|0000    ^            | <------- Lightweight Container

					|0000   / \           |

				   '=====================' <------- Frictionless surface

					<-------  L  --------->

Hi guys,

Here is an excellent example (exception) to show it is not necessary that a static object moves ONLY under an application of external force.

A container is resting on a frictionless surface. It is of length ?'L'. The container is made up of a lightweight but strong plastic that is capable of holding a weight of a ton (1000 Kg).

There are a thousand 1 kg cannon balls in a sac on the left side of container. A chimp throws these balls to the right side where another sac is hanged. One by one these balls get accumulated in that right side sac. The container, sacs and chimp's weight collectively make 10 Kg which is 1% of the overall weight of the system & can be neglected.

STAGE 2: Chimp throwing cannon balls to other side

Code:

				.---------------------.

				|o            .       |

				|oo          . o      |

				|ooo     _  .   .     |  

				|ooo    (ö).     .   o| <------- Lightweight Container

	  Old CM-->#00   \|/       . oo<---------- Balls on Right Side 

				|0000    ^         000|

				|0000   / \       0000|

				'=====================' <------- Frictionless surface

				<-------  L  --------->

After all balls are moved from left side to right side, the center of mass shifts from left & all balls were accumulated to the high density right side. But center of mass has to shift under the application of the external force which is 0 in our case. So system moves on the left side by distance L to adjust the center of mass at the same vertical Line in the reference frame. So for anybody standing outside the container, the container should mov by a distance L into its left from right side.

See figure below:

STAGE 3: Static Container with Center of Mass on Right Side as MOST of the mass is accumulated on Right

Code:

<======== Container Moved to Left side by nearly a distance of L to adjust Center of Mass on Same Refernece Line bcoz Center of Mass cannot move bcoz external force is zero



.---------------------.

|                    o|

|                   oo|  

|     _            ooo|  

|    (ö)           ooo| <------- Lightweight Container

|    /|\          00#<---------- New center of Mass

|     ^           0000|

|    / \          0000|

'=====================' <------- Frictionless surface

<-------  L  --------->

So with a near perfection in the above figures you guys look at STAGE 1 and STAGE 3 carefully.

The Center Of Mass indicated as '#' is on same vertical line indicating that center of mass does not move as there is no external force applied but because it is shifted inside the container, container has to shift its position to a little left in order to bring center of mass (STAGE 3) on the same vertical line that passed through old center of Mass (STAGE 1).

Isn't that amazing?

Amazing fact: Can this Container Move?

Related Topics

Quick Links

My Account

able2know