# Calculating Force of 25 lb Bag Hitting Object

• kgtp1999
In summary, the conversation discusses the process of determining the force that hits an object when a 25 lb. bag is released from a 7 ft rope and swings until it is 5 ft from the object. The force depends on the elastic properties of the objects and the stopping distance. If the stopping distance is 0, the velocity of the bag before impact must be calculated to determine the force.
kgtp1999
Initially, a 25 lb. bag is hanging straight down from a 7 ft rope at the center of an object next to a vertical wall. The 25 lbs is raised until it is about 45 degrees or 5 ft from the object and then released. How do I determine the force that hits the object? I am only looking for a simple approximation without the weight of the rope or wind.

When you release the pendulum it converts gravitational potential energy (GPE) of the raised weight at 45 degrees, to kinetic energy (KE) of impact. You can easily find GPE and KE but if I recall properly the force during collision depends on the elastic properties of the bodies. Also it is not clear what the "object" is in your problem statement.

Edit: hyperphysics treats the basic concept of impulse force here:

http://hyperphysics.phy-astr.gsu.edu/HBASE/Impulse.html

The formula Favg*d = -(1/2)m*v^2 appears at the link page and might solve your problem if stopping distance "d" can be estimated as the bag comes to a stop as it hits the object.

Last edited:
The object is a plastic prototype secured to the wall. When the bag hits it the object has no substantial elasticity. So given the stopping distance is 0, would it be just a matter of finding the velocity as the weight is about to hit the object?

## 1. What is the formula for calculating force?

The formula for calculating force is force = mass x acceleration (F = ma).

## 2. How do I determine the mass of the object?

To determine the mass of the object, you can use a scale or balance to measure the weight of the object in kilograms (kg). If the weight is given in pounds (lb), you can convert it to kilograms by dividing by 2.2.

## 3. What is the acceleration of an object?

Acceleration is the rate at which an object's velocity changes. It is measured in meters per second squared (m/s²). If the object is not accelerating, the acceleration value will be 0.

## 4. How do I calculate the force of a 25 lb bag hitting an object?

To calculate the force of a 25 lb bag hitting an object, you will need to know the mass of the bag and the acceleration at which it hits the object. Once you have those values, you can use the formula F = ma to calculate the force in newtons (N).

## 5. What are the units for force?

The units for force are newtons (N). However, in some cases, force may also be measured in pounds (lb) or other units of weight. It is important to make sure all units are consistent when using the formula F = ma.

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