# Need help on a forces and equilibrium question

• question dude
In summary, the conversation is about a question regarding the support force acting on a girder on a slope. The person is confused about why the support force is not acting vertically upwards and assumed it would always be perpendicular to the ground. However, it is explained that there could be surface friction or an obstruction causing the support force to not be completely perpendicular.
question dude
Its part B that I'm not sure about.

I know how to do it. But I'm confused about why the support force is not acting vertically upwards (so no horizontal component).

I assumed that the support force would always be directly perpendicular to the ground/slope/wall.

Can someone explain this?

question dude said:
[ img]http://www.thestudentroom.co.uk/attachment.php?attachmentid=197381[/PLAIN]

Its part B that I'm not sure about.

I know how to do it. But I'm confused about why the support force is not acting vertically upwards (so no horizontal component).

I assumed that the support force would always be directly perpendicular to the ground/slope/wall.

Can someone explain this?
Apparently the lower end of the girder is not free to slide along the ground. Maybe it's digging into the ground or perhaps, it's prevented from sliding to the left by some obstruction.

SammyS said:
Apparently the lower end of the girder is not free to slide along the ground. Maybe it's digging into the ground or perhaps, it's prevented from sliding to the left by some obstruction.

does this count as surface friction of the ground, or is it totally different?

It could be friction, it could be some obstruction against which the beam is resting, whatever.

SteamKing said:
It could be friction, it could be some obstruction against which the beam is resting, whatever.

oh I see then, so the only reason why the support force in this question isn't acting perpendicular is because the ground isn't totally smooth, right?

For the purpose of this problem, yes.

## 1. What is a force?

A force is a push or pull acting on an object. It can cause an object to accelerate, decelerate, change direction, or change shape.

## 2. What is equilibrium?

Equilibrium occurs when all forces acting on an object cancel each other out, resulting in a state of balance. This means that the object will either remain at rest or continue to move at a constant velocity.

## 3. How do you calculate net force?

To calculate net force, you must first determine all the individual forces acting on an object. Then, use the equation Fnet = ma, where Fnet is the net force, m is the mass of the object, and a is the acceleration. This will give you the overall force acting on the object.

## 4. What is the difference between a balanced and unbalanced force?

A balanced force occurs when all forces acting on an object are equal in magnitude and opposite in direction, resulting in a state of equilibrium. An unbalanced force, on the other hand, occurs when the forces are not equal and the object will experience a change in motion.

## 5. How does the direction of a force affect equilibrium?

The direction of a force can determine whether an object is in a state of equilibrium or not. When all forces are acting in the same direction, the object will continue to move at a constant velocity. When forces are acting in opposite directions, the object will either accelerate or decelerate depending on the magnitude of the forces.

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