# Impaction Energy of hammer

• iliepins
In summary, if the mass of the head of the hammer is M1 and the mass of the handle is M2, then the mass to be used at the impaction point is M = M1 + M2.

#### iliepins

Looking for quidance on calculating the mass at an impaction point of a swinging hammer. The hammer is set up to be swung pneumatically just at the edge of the handle in the horizontal plane. I understand the calculation E=1/2mv^2. Velocity is being measure just before the impaction point. So I'm happy with that and know the value. Let say v=5m/s. The question is on mass. the hammer head has a mass M1 and the handle has a mass M2. What is the mass to be used at the impaction point. M2, M2+M1, center of mass (but then how do i figure that), some other method? I want to simply calculate the energy being imparted at that point.

Since it is a rotational motion, I'd instead find the moment of inertia I of the hammer about the axis of rotation at the end of the handle, and then use the formula for the kinetic energy of the rotational motion at angular velocity w:

E = 1/2 * I * w^2

As an approximation, consider the hammer as consisting of two parts. Approximate the metal head with mass M1 at radius r=R1, and e.g. a rod of some mass M2 going from r=0 to r=R1 (assuming homogeneous mass distribution along its length).

The moment of inertial about r=0 of the head in this approximation is I_h = M1*R1^2 since we are approximating it as a point.

The moment of inertial about r=0 of a radial rod of mass M2 of length R1 is (from looking it up on wikipedia) I_r = 1/3 * M2 * R1^2 (please double-check this...)

Thus, the moment of inertial about r=0 of the entire hammer in this approx is I = I_h + I_r.

Then the kinetic energy if the hammer is E = 1/2 * I * w^2 where w is the angular velocity (in radians per second) of the rotational motion upon impact.

It is of course possible to find a more accurate moment of inertia of the hammer by not assuming the head to be located at one point.

Of course, if the head is much more massive than the handle, then your can just approximate everything by incoming linear motion of the head at v=5m/s.

welcome to pf!

hi iliepins! welcome to pf! iliepins said:
Looking for quidance on calculating the mass at an impaction point of a swinging hammer. The hammer is set up to be swung pneumatically just at the edge of the handle in the horizontal plane. I understand the calculation E=1/2mv^2.

why do you want the energy?

the effect is measured by the momentum of the hammer, p = mv (or by the angular momentum, Iω, if the hammer is too extensive) ## 1. What is the impaction energy of a hammer?

The impaction energy of a hammer is the amount of kinetic energy that is transferred to an object when the hammer strikes it. It is a measure of the force and velocity of the hammer's impact.

## 2. How is the impaction energy of a hammer calculated?

The impaction energy of a hammer is calculated by multiplying the mass of the hammer by the square of its velocity and dividing by 2. This equation is represented as E = (m x v^2)/2, where E is the impaction energy, m is the mass of the hammer, and v is the velocity of the hammer.

## 3. What factors affect the impaction energy of a hammer?

The impaction energy of a hammer is affected by the mass and velocity of the hammer, as well as the hardness and density of the object being struck. The height from which the hammer is dropped and the angle at which it strikes also play a role in determining the impaction energy.

## 4. How does the impaction energy of a hammer impact the force of impact?

The impaction energy of a hammer is directly proportional to the force of impact. This means that as the impaction energy increases, so does the force of impact. A higher impaction energy will result in a more powerful impact, capable of causing more damage or breaking through tougher materials.

## 5. What are some real-world applications of understanding impaction energy of a hammer?

Understanding the impaction energy of a hammer is crucial in various industries, such as construction, demolition, and manufacturing. It helps engineers determine the appropriate type and size of hammer to use for a specific task, as well as the amount of force needed to complete the task. It also aids in predicting the potential damage a hammer may cause and implementing safety measures to prevent accidents.