What is work, units, example
What is work, units, example
Define work:
In physics, "work" refers to the amount of energy that is transferred when an object moves over a distance while being acted upon by an outside force, at least some of which is directed in the direction of motion.
The length of the path is multiplied by the component of the force acting along the path to get the amount of work if the force is constant.
Mathematically:
The work W is equal to the force f times the distance d, which is how this idea is formally expressed.
i.e. W = f.d
When a force is applied at an oblique angle to a displacement, the work done is
W = fd cos θ
In addition to shifting a body's entire composition, work may also be performed on it by compressing a gas, turning an axis, or even moving particles that are undetectable to the naked eye. body is the cause. a magnetic field outside of the body.
Dimention of work:
As defined by [ML2T–2], the magnitude of work is equal to the magnitude of energy.
Unit of work:
The joule (J), the SI unit of work, is defined as the amount of work required to move an item one metre in the direction of a force of one newton (N).
Keep in mind that 1 J equals 1 N m equals 1 kg .m2/s2.
For instance, if an object moves 2 metres after being subjected to a 5 newton force, 10 newton metres (10 joules) of work were accomplished.
Factors affecting work:
Let's now examine the variables on which the work performed by the force on the item depends.
Force:
Any object with mass can modify its speed and acceleration due to force, which is defined as a push or pull. Having both a magnitude and a direction, force is a vector quantity.
Displacement:
The vector variable known as displacement provides the shortest distance between an object's start and end positions. If a force acting on an object results in no net displacement in that force's direction, then no net work is performed by that force on that object. We can say that no work has been done on a wall, for instance, if we press firmly against a solid wall and it does not budge.
Angle Between Force and Displacement:
Work is directly inversely proportional to the cosine of the angle between force and displacement for constant force and constant displacement.Depending on how much the angle between force and displacement matters, there are different operating modes.
Special cases:
1. The direction of the force and the direction of the displacement are identical if the angle between them is zero. The job done in this situation is at its highest level.
W is equal to F x cos 00 x d, where cos 00 equals 1.
2. If the force and displacement make a 900-degree angle, the force's direction is parallel to the displacement's direction. Work has not been done in this instance.
Cos 900 = 0, hence W = F x cos 900 x d = 0.
3. When a force is applied to an item, work is referred to as positive work.
4. When a force is applied to an object, the work is referred to as negative work.
180 ≤ θ < 90°
We've learnt what work is thus far in this article, as well as the mathematical definition of scientific work and the definition of work in physics.
Work examples in daily life:
Physics plays a vital role in various aspects of our daily lives.
Lifting Objects: When you lift a book or other object off the ground, you are applying a force at a distance to overcome gravity. The work done is given by W = F × d, where W is the work done, F is the force applied, and d is the distance over which the force acts.
Pushing or pulling a cart: When you push or pull a cart, you are applying force to move it. The work done depends on the magnitude of the force and the distance traveled by the carriage.
Cycling: When you pedal your bike, you apply force to the pedals, which causes the bike to move. The work done is equal to the force multiplied by the distance traveled.
Use of household appliances: When you turn on an electrical device such as a television or refrigerator, it is working to transfer electrical energy to the device. The amount of work performed depends on the electricity consumption of the electrical device and the time of its use.
Stair Climbing: When you go up a flight of stairs, you exert a force against gravity to lift your body to a higher level. The work done is equal to the force applied multiplied by the vertical distance traveled.
Ball Bounce: When you hit the ball, you apply force to it, causing it to change direction and gain height. The work done is transferred to the ball in the form of kinetic energy.
Opening a door: When opening a door, force is applied to turn the handle against the resistance of the friction and weight of the door. The work done is equal to the force applied multiplied by the angle of rotation of the handle.
Numerical problems:
Let's tackle some basic tasks at work to better understand the concepts.
1. The body moved 2 m when a force of 10 kN was applied. Calculate the work done on the body.
Answer: The work done is determined by the product of force and displacement. Then the work is done
W = F d
Where F = 10 kN = 10000 N and d = 2 m
Substituting the values into the formula, we get
W = 10000 x 2 = 20000 Nm or 20000 J.
So the work on the body is 20,000 J.
2. The student drags the box along an inclined plane with a force of 15 kN. If the body was moved 3 m with an inclination of 600. Calculate the student's work on the body.
Answer: The force exerted by the student to pull the box down the inclined plane is F = 15 kN = 15000 N.
The body has moved 3 m, so d = 3 m. The angle of inclination between force and displacement is θ = 600.
Therefore, the formula for the work done is W = F x cos θ x d
Substituting the values into the formula, we get
W = 15000 x cos 600 x 3
cos 600 = ½
So W = 15000 x (½) x 3 = -22500 Nm or -22500 J.
Here the student pulls on the box so that the box acts on the student. Therefore, the work done is bad.
The work on the body is -22500 J.
3. An object is pulled horizontally across a surface by a force of 100 N acting parallel to the surface. Calculate the work done by the force when moving the body over a distance of 8 m.
Solution:
F=100N, d=8m
Since F and d point in the same direction, θ = 0, [θ is the angle of the force relative to the direction of motion], so
W = FdCosθ
B = 100 x 8 x Cos 0
W = 800 J [Since Cos 0 = 1]
Conclusion:
Work has a different meaning in science than in real life. Working doesn't mean the hard work is over. Acting force and displacement in the direction of the force are two terms of doing work in physics.
What's Your Reaction?
