SI Unit of Work| Definition, and Examples

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The work formula equals the force applied to an object multiplied by the distance applied.
Work (joules) = force (newtons) x distance (meters)
where a joule is the SI unit of work. For instance, Lifting a weight from the ground and placing it on a shelf is a simple example of work. This article defines work, defines the SI unit of work, and provides instances of work done.

Definition of Work

Work is defined as force applied across a distance. Examples of work include pushing an object against gravity, driving a car up a hill, and lowering a captive helium balloon. Work is the mechanical expression of energy.

SI Unit of Work

The SI unit of work is the joule (symbol: J). A joule is the kinetic energy of a kilogram mass traveling at one meter per second (one joule = a kg.m²/sec²). In simple words, It is also the amount of work done on an object when a force of one newton operates in the direction of the object’s motion over a one-meter distance (1 joule equals one newton meter or Nm).
Here are some instances of joule work:

• If a newton (0.22 pounds, or 3.6 ounces) object is hoisted to a height of one meter (3 feet, 3.3 inches). One joule of work is completed.
• When a force of 10 newtons is applied to a moving object of 2 meters, the work done is 20 newtons-meter or 20 joules.
• A person generates roughly 135-150 joules with an average punch. That’s equivalent to throwing a basketball from a 15-story skyscraper.

SI unit of work = Joule

One Joule = N.m = Kgm2/sec2

Another unit of work is erg

One erg = dyne – centimeter (dyn · cm)

One erg = g · cm 2 /sec 2

Solved Problems of Work (SI Unit)

Here are a few solved examples of the SI unit of work:

1. A 10 kg object is elevated vertically by a height of 5 meters. What is the amount of work done on the object?

The amount of work done can be determined using the equation W = mgh, where m is the item’s mass, g is gravity’s acceleration (9.8 m/s2), and h is the height the object was lifted

W = 10 kg * 9.8 m/s^2 * 5 m = 490 J (joules)

As a result, the total amount of work done on the object is 490 J.

2. To move an object over a distance of 20 meters, a force of 100 N is applied. How much work has been done on the object?

The amount of work done can be calculated using the equation W = Fd, where F is the applied force and d is the distance travelled.

W = 100 N * 20 m = 2000 J (joules)

As a result, the total amount of work done on the object is 2000 J. These examples demonstrate how to calculate work done with the SI unit of joules (J).

Can work be negative?

When a force operating on a body displaces it in the direction of a force, work is done. For example, when a force of 1 Newton is exerted over a distance of 1 meter, the work done by a moving object equals 1 Joule. Work can be negative or positive since the applied force can be negative or positive.
Negative work is illustrated by the motion of a body against the force of friction.

Energy

The ability to do work is called energy and work is moving something against a force, like gravity.
Energy is a material attribute that may be turned into work, heat, or radiation. In layman’s terms, energy is the ability to perform tasks. When we work on anything, part of our energy is transferred to that thing. When energy is transmitted, the thing that is doing the work acquires energy. Energy is separated into two types by science: kinetic energy and potential energy. The joule is the SI unit of energy (J).

Work-Energy Theorem

The work done by the total of all forces acting on an item equals the change in kinetic energy of the object. According to the work-energy theorem (or), the net work done on a system equals the change in kinetic energy. For details, please check the article “Work energy theorem”.

Gravitational Potential Energy

When an object is lifted to a higher elevation, work is done on it and the transferred energy is stored; the amount of energy stored is mgh. This stored energy is gravitational potential energy, which has the formula w = mg. The phrase “potential” refers to this energy’s ability to perform work when the object’s potential is decreased. Gravitational energy is demonstrated by a weight lifted vertically, water stored in a dam, a child at the top of a slide, water pouring from a faucet, and a ball held in the air.

Summary

• The Joule (J) is the SI unit of work or energy. It is defined as the amount of work done when a force of one Newton is applied over a one-meter distance in the force’s direction.
• Work is defined as the force exerted to an item multiplied by the distance traveled.
• Work (joules) equals force (newtons) multiplied by distance (meters), where a joule is a SI unit of work.
• The joule is the unit of work. A joule is the amount of work done when a force of one Newton is applied across a one-meter distance.

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Frequently Asked Questions

1. What is malleability?

Malleability refers to a substance’s ability to distort under pressure. The material can be pounded or rolled into thin sheets if it is pliable. Metal malleability refers to the ability of a metal to deform under compression and take on a new shape.

2. Hydro turbines?

Hydro turbines are devices used in hydroelectric power plants to transmit energy from flowing water to a rotating shaft, where it is converted into electricity. In response to the infusion of water into their blades, these turbines revolve or spin.

3. Can force be negative?

Yes, force may be negative since it is a vector quantity that is affected by magnitude and direction. The negative symbol just denotes the direction.

4. Can displacement be negative?

Yes, because displacement is a vector quantity that depends on magnitude and direction, it can be negative. The negative symbol just denotes the direction.
Check the full article “can displacement be negative?”.

5. What is uniform circular motion?

The constant-speed motion of an object in a circle is characterized as a uniform circular motion. A uniform circular motion object moves at a consistent pace. Despite this, it is accelerating as a result of its change in direction. The acceleration is inwardly directed.

6. Linear motion?

linear motion is movement along a straight line, whereas nonlinear motion is any movement that is not along a straight line. Linear motion could be uniform or non-uniform.

7. Spring constant?

The spring constant, k, is a measure of the spring’s stiffness. It varies depending on the spring and material. The greater the spring constant, the stiffer the spring and the more difficult it is to stretch.

8. Light energy definition?

Light energy is a kind of electromagnetic radiation that is visible to the human eye. Photons are the particles that make light, and they are like small packets of energy. The Sun is the nearest star to Earth and emits light energy. Check the full article “Light energy definition”.

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