# What force is the pin exerting on the rod?

• AirJersey
In summary, a thin rod of uniform mass M and length L is attached to a string at one end to the ceiling and a pin at the other end to the wall. The rope connecting the ceiling and the horizontal rod is cut at t = 0 s. The force of the pin at t = 0 seconds is mg/4 and the tension of the rope is mg/2. When the rod swings vertically, the pin exerts a force on the rod. When the rod reaches the vertical part of its swing, its angular speed is related to how much it has rotated by using the conservation of energy. If the initial position of the rod was almost vertical, the force of the pin when it reaches the horizontal position would be mg
AirJersey
A thin rod of uniform mass M and length L is attached to a string at one end to the ceiling and a pin at the other end to the wall. The rope (connecting the ceiling and the horizontal rod) is cut at t = 0 s.

1) What is the force of the pin at t = 0 seconds?

2) When the rod swings vertically, what force is the pin exerting on the rod?

3) When the rod reaches the vertical part of its swing, what is the rod's angular speed and angular acceleration?

4) If the initial position of the rod was almost vertical, what would be the force of the pin when it has reached horizontal position.

L/2 mg sin90 = I $$\alpha$$

I got force of pin for the initial condition = mg/4 and tension of rope = mg/2. A t=0 accerlation of center of mass I got -3/4g. All the above questions I have no idea how to set up.

Start with a free-body diagram. You will find that you need a relationship between the angular speed of the rod and how much it rotated by. No problem: use the conservation of energy.

## 1. What is the definition of force?

Force is a physical quantity that can change the motion or shape of an object. It is typically measured in units of Newtons (N).

## 2. How is force related to the pin and the rod?

The force exerted by the pin on the rod is known as contact force. This force is the result of the interaction between the pin and the rod when they are in contact with each other.

## 3. What factors affect the force exerted by the pin on the rod?

The force exerted by the pin on the rod depends on the magnitude of the force applied by the pin, the surface area of contact between the pin and the rod, and the material properties of both the pin and the rod.

## 4. How can the force exerted by the pin on the rod be calculated?

The force exerted by the pin on the rod can be calculated using the formula F = μN, where F is the force, μ is the coefficient of friction between the pin and the rod, and N is the normal force between the two surfaces.

## 5. Can the force exerted by the pin on the rod be negative?

Yes, the force exerted by the pin on the rod can be negative if the pin and the rod are moving in opposite directions. This indicates that the pin is exerting a force in the opposite direction of motion on the rod.

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