Work, Energy and Power
To find the force of impact, you need to know kinetic energy (mass x 1/2 x velocity squared) and distance over which the impact took place. In modern physics the terms mass and energy are often used synonymously. And force changes particle's kinetic energy. Also in thermodynamics, a force can. When a force acts over a distance, Energy is created. If we lift up an item with mass, in a gravitational field, we create potential Energy. If we slide an item that.
Energy and Work
Meanings of the strict formula[ edit ] This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources.
Unsourced material may be challenged and removed. February The mass—energy equivalence formula was displayed on Taipei during the event of the World Year of Physics Mass—energy equivalence states that any object has a certain energy, even when it is stationary.
In Newtonian mechanicsa motionless body has no kinetic energyand it may or may not have other amounts of internal stored energy, like chemical energy or thermal energyin addition to any potential energy it may have from its position in a field of force. In Newtonian mechanics, all of these energies are much smaller than the mass of the object times the speed of light squared.
In relativity, all the energy that moves with an object that is, all the energy present in the object's rest frame contributes to the total mass of the body, which measures how much it resists acceleration.
Each bit of potential and kinetic energy makes a proportional contribution to the mass. As noted above, even if a box of ideal mirrors "contains" light, then the individually massless photons still contribute to the total mass of the box, by the amount of their energy divided by c2. In a nuclear reaction, the mass of the atoms that come out is less than the mass of the atoms that go in, and the difference in mass shows up as heat and light with the same relativistic mass as the difference and also the same invariant mass in the center of mass frame of the system.
In this case, the E in the formula is the energy released and removed, and the mass m is how much the mass decreases. In the same way, when any sort of energy is added to an isolated system, the increase in the mass is equal to the added energy divided by c2.
An object moves with different speed in different frames, depending on the motion of the observer, so the kinetic energy in both Newtonian mechanics and relativity is frame dependent.
This means that the amount of relativistic energy, and therefore the amount of relativistic mass, that an object is measured to have depends on the observer.
The rest mass is defined as the mass that an object has when it is not moving or when an inertial frame is chosen such that it is not moving. The term also applies to the invariant mass of systems when the system as a whole is not "moving" has no net momentum. The rest and invariant masses are the smallest possible value of the mass of the object or system. They also are conserved quantities, so long as the system is isolated.
Because of the way they are calculated, the effects of moving observers are subtracted, so these quantities do not change with the motion of the observer. The rest mass is almost never additive: The rest mass of an object is the total energy of all the parts, including kinetic energy, as measured by an observer that sees the center of the mass of the object to be standing still. The rest mass adds up only if the parts are standing still and do not attract or repel, so that they do not have any extra kinetic or potential energy.
The other possibility is that they have a positive kinetic energy and a negative potential energy that exactly cancels. Binding energy and the "mass defect"[ edit ] This section needs additional citations for verification.
July Learn how and when to remove this template message Whenever any type of energy is removed from a system, the mass associated with the energy is also removed, and the system therefore loses mass. However, use of this formula in such circumstances has led to the false idea that mass has been "converted" to energy. This may be particularly the case when the energy and mass removed from the system is associated with the binding energy of the system.
In such cases, the binding energy is observed as a "mass defect" or deficit in the new system. The fact that the released energy is not easily weighed in many such cases, may cause its mass to be neglected as though it no longer existed.
This circumstance has encouraged the false idea of conversion of mass to energy, rather than the correct idea that the binding energy of such systems is relatively large, and exhibits a measurable mass, which is removed when the binding energy is removed. The difference between the rest mass of a bound system and of the unbound parts is the binding energy of the system, if this energy has been removed after binding.
For example, a water molecule weighs a little less than two free hydrogen atoms and an oxygen atom. You could apply the projectile motion equations, or you could think of the situation in terms of energy actually, one of the projectile motion equations is really an energy equation in disguise. If you drop an object it falls down, picking up speed along the way. This means there must be a net force on the object, doing work. This force is the force of gravity, with a magnitude equal to mg, the weight of the object.Force Work and Energy Relationship - Videos for Kids by omarcafini.info
The work done by the force of gravity is the force multiplied by the distance, so if the object drops a distance h, gravity does work on the object equal to the force multiplied by the height lost, which is: An object with potential energy has the potential to do work. In the case of gravitational potential energy, the object has the potential to do work because of where it is, at a certain height above the ground, or at least above something.
Spring potential energy Energy can also be stored in a stretched or compressed spring. An ideal spring is one in which the amount the spring stretches or compresses is proportional to the applied force.
This linear relationship between the force and the displacement is known as Hooke's law. For a spring this can be written: The larger k is, the stiffer the spring is and the harder the spring is to stretch. If an object applies a force to a spring, the spring applies an equal and opposite force to the object.
This is a restoring force, because when the spring is stretched, the force exerted by by the spring is opposite to the direction it is stretched. This accounts for the oscillating motion of a mass on a spring.
Explain how force, energy and work are related?
The energy of a moving object is called kinetic energy, and is equal to one half of the object's mass times the square of its velocity: When thinking about the impact force of a falling object, you can calculate the energy of the object at its point of impact if you know the height from which it was dropped.
This type of energy is known as gravitational potential energy and it is equal to the object's mass multiplied by the height from which it was dropped and the acceleration due to gravity: Impact and Work Work occurs when a force is applied to move an object a certain distance. Therefore, work is equal to force multiplied by distance: Because force is a component of work and an impact is the conversion of energy into work, you can use the equations for energy and work to solve for the force of an impact.
The distance traveled when the work is accomplished by an impact is called the stop distance. It is the distance traveled by the moving object after the impact has occurred.
Sciencing Video Vault Impact From a Falling Object Suppose you want to know the impact force of a rock with a mass of one kilogram that falls from a height of two meters and embeds itself two centimeters deep inside of a plastic toy.