# Required force to hold or pull inclined object downwards.

• AK93
In summary, the problem is to calculate the minimum force (F) is required to hold the lens-shaped object in position, assuming it is not rotating.
AK93
Thread moved from a technical forum to the schoolwork forums
Can somebody help me to solve this problem and guide? I need to calculate minimum force (F) (Newtons or kilograms) is required to pull down object (K1) to (K2), or to hold it in position. Angle between (K1) and (K2) = 50 degrees. Using mounting points (P1) and (P2). (K1) mass = 3.5 ton, (A) Length = 9 meters, (B) Height = 3.5 meters. Mounting points (P1) and (P3 is on a hinge) distance from center = 75centimeters, (C) = 1.3 meters in total. Height from point (P1) to (P2) is 1.7 meters.

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Welcome to PF.

First, you will need to identify the position of the centre of mass of k1.

But gravity will not be your biggest problem. The wind will be more important. You must model k1 for wind loading at different elevation angles and wind directions. Is this structure in a region subjected to hurricane force winds?

AK93
Welcome!
What have you calculated so far?
Could you show us your work?

Where will the pulling force be applied?
At what point will the round upper surface hit the flat lower surface?

AK93
Lnewqban said:
Welcome!
What have you calculated so far?
Could you show us your work?

Where will the pulling force be applied?
At what point will the round upper surface hit the flat lower surface?
Thanks for the nice greeting,
I haven't done any calculations. Thats why Iam asking for a guide and help, how should I calculate the forces. P1 and P2 must meet, so K1 will be looking upwards. Biggest question, how much force is needed to hold it in position or pill it downwards so K1 wouldn't flip to the left side. I can find the center of the K1, what else should be done to calculate this?

Once K1 is looking upwards, the centre of mass will be above K2, between the hinge and point P2. K1 will then be resting on K2, with P1 pressed against P2. Force will not be needed to hold K1 down.

The mass of K1, and the position of the centre of mass of K1 are needed.

The line from the hinge pin, P3, to the centre of mass forms a radial arm. When that arm points directly upwards, no torque will be needed to balance K1. Either side of that balance point, an angle and mass dependent force will be required.

We can explain to you what is important, but you must employ a qualified mechanical engineer before you actually build anything.

Lnewqban and AK93
First, please clarify if this is a real world problem, as @Baluncore seems to assume, or an academic exercise.

Second, is the lens-shaped object a spherical cap or a segment of a cylinder?
AK93 said:
minimum force (F) (Newtons or kilograms) is required to pull down object (K1) to (K2), or to hold it in position.
Those are not the same thing. The force required to hold it in the position shown may well be less than is required at some point in rotating the lens-shaped object into that position from a more horizontal one. (Note that it cannot be completely horizontal.)
Indeed, if the diagram is drawn accurately I would say the force needed to hold it steady will be one that stops it tipping further.

Which is sought?

Lnewqban

## 1. What is the required force to hold an inclined object downwards?

The required force to hold an inclined object downwards is equal to the weight of the object multiplied by the sine of the angle of inclination.

## 2. How is the angle of inclination calculated?

The angle of inclination is calculated by dividing the height of the inclined object by the length of the base. This can also be represented as the inverse tangent of the height divided by the length of the base.

## 3. Does the weight of the object affect the required force?

Yes, the weight of the object directly affects the required force to hold or pull it downwards. The heavier the object, the greater the required force.

## 4. What is the relationship between the angle of inclination and the required force?

The required force to hold or pull an inclined object downwards increases as the angle of inclination increases. This means that the steeper the incline, the more force is needed to hold or pull the object downwards.

## 5. Can friction affect the required force to hold or pull an inclined object downwards?

Yes, friction can affect the required force to hold or pull an inclined object downwards. If there is friction present, the required force will be greater as it must overcome the resistance of the friction as well.

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