Find minimum force to tip block

In summary, the problem involves finding the magnitude of a force F applied at point A that is just enough to tip over a block of mass M, which will rotate about its bottom right corner. The correct answer is MgL/2H, with gravity playing a role in this and the distance between the center and the rotational axis being H. The torque created by the force F is calculated by multiplying force and perpendicular distance.
  • #1
vu10758
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A force F applied at point A is just large enough to tip over a block of mass M. The block will rotate about its bottom right corner. Find the magnitude of F.

The picture for this is problem 13 at this link http://viewmorepics.myspace.com/index.cfm?fuseaction=viewImage&friendID=128765607&imageID=1460084048

The know that torque is force x radius, and the radius here is L.
The correct answer is MgL/2H, so I suspect that gravity somehow plays a role in this. However, I don't know what to do. How is this horizontal force F be related to gravity? Where does the 2H come from?
 
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  • #2
vu10758 said:
A force F applied at point A is just large enough to tip over a block of mass M. The block will rotate about its bottom right corner. Find the magnitude of F.

The picture for this is problem 13 at this link http://viewmorepics.myspace.com/index.cfm?fuseaction=viewImage&friendID=128765607&imageID=1460084048

The know that torque is force x radius, and the radius here is L.
The correct answer is MgL/2H, so I suspect that gravity somehow plays a role in this. However, I don't know what to do. How is this horizontal force F be related to gravity? Where does the 2H come from?
Could you draw where the gravity acts on the block? And thus make a FBD
 
  • #3
I would have mg pointing down from the center of the block and N pointing up. I would also have friction pointing to the left. The distance between the center and the rotational axis is H. However, why do we multiply this mg by L when L is the horizontal distance. Does this have anything to do with friction, but I don't see mu in the answer. I know that normal force is equal to mg, but I don't know if that will help. When looking at torque, shouldn't I have F*L = mg*H and then have F = mg*H/L. However, this is not right.
 
Last edited:
  • #4
Because what you are interested is the perpendicular distance. The vector L is perpendicular to the force mg, thus the torque mg applies is mg*L/2

What is the torque that the force F creates? force * perpendicular distance
 
  • #5
Oh I see now. Thanks very much.
 

Related to Find minimum force to tip block

1. What is the concept of "minimum force to tip block"?

The concept of "minimum force to tip block" refers to the minimum amount of force required to cause a block to tip over. This force is dependent on the weight and dimensions of the block, as well as the surface on which it is resting and the angle at which the force is applied.

2. How is the minimum force to tip block calculated?

The minimum force to tip block can be calculated by using the formula F = (M * g * h) / d, where F is the minimum force, M is the mass of the block, g is the gravitational acceleration, h is the height of the center of gravity of the block, and d is the distance from the center of gravity to the edge of the block.

3. What factors can affect the minimum force to tip block?

The minimum force to tip block can be affected by several factors, including the weight and size of the block, the surface on which it is resting, the angle at which the force is applied, and any external forces acting on the block (such as wind or vibrations).

4. How can the minimum force to tip block be increased?

The minimum force to tip block can be increased by increasing the weight or size of the block, lowering the center of gravity by adding weight to the bottom of the block, or by increasing the friction between the block and the surface on which it is resting.

5. Why is it important to know the minimum force to tip block?

Knowing the minimum force to tip block is important for safety purposes, as it can help determine the stability and potential tipping point of objects in various settings such as construction sites, warehouses, or transportation. It can also be useful in designing and engineering structures to ensure they can withstand external forces without tipping over.

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