Drag Force Formula Electric Flux Formula Energy Formula Physics
Drag Force Formula
In commonly used context drag force is the force that is exerted on a solid body moving with respect to a fluid due to the movement of the fluid. For example drag on a ship moving in water or drag on a plane moving in the air. Therefore a drag force is the resistance force caused by the motion of a body through a fluid like water or air. This drag force acts opposite to the direction of the oncoming flow velocity. Therefore, this is the relative velocity between the body and the fluid. In this article, we will discuss the concept and drag force formula with examples. Let us learn the concept!
Source: en.wikipedia.org
Drag Force Formula
Concept of Drag Force
Drag force is the resistance force of a fluid. This force applies acting opposite towards the motion of the object which is moving submerge in a certain fluid. Thus Drag Force is defined as the force which resists the motion of a body with fluid.
If such motion of the body exists in the fluid-like air then it is known as aerodynamic drag. Also, if the fluid is water then it is a hydrodynamic drag. Its nature is to act in the opposite direction to the flow of velocity.
Air resistance always limits the terminal speed which a falling body can reach. Here air resistance is an example of the drag force, which is the force that objects feel when they move through a fluid.
Similar to kinetic friction, drag force is of reactive nature because it only exists when the object is moving and it points in the opposite direction to the motion of the object through the fluid.
This force can be broken into two types such as form drag and skin drag. Form drag is caused by the resistance of the fluids to being pushed out of the way by an object in motion through the fluid.
Therefore, form drag is similar to the normal force provided by the resistance of solids to being deformed. Skin drag is essentially a kinetic frictional force caused by the sliding of the fluid along the surface of the moving object.
Its value is directly dependent on Fluid density, Square of the velocity, Drag coefficient, and Cross-section area.
The formula for Drag Force
Since,
Therefore, mathematically,
Where,
| D | Drag Force |
| It is the drag coefficient | |
| It is the density of the medium in | |
| V | It is the velocity of the body in |
| A | It is the cross-sectional area in m² |
Solved Examples on Drag Force Formula
Q.1: A vehicle travels with a speed of 80 km per h, with a drag coefficient of 0.25. If the cross-sectional area is 6 square meters, then find out the drag force.
Solution:
Velocity, V = 80 km per h = 80×518mpersec=22.22mpersec .
Drag coefficient, Cd=0.25
Cross-sectional area, A =6 square meter
Density of fluid, ρ=1.2kgpercubicm
The drag force formula is:
Substituting the values,
Therefore the drag force will be 444.35 N.
Electric Flux Formula
In this topic, we will discuss the important concept of electric flux, its computation. Also, an analogy between the flux of an electric field and that of water will be explained. Electric flux is an important property of an electric field. It can be considered as the number of forces that are intersecting a given area. Electric field lines are generally considered to start on positive electric charges and to finish on negative charges. Field lines directed into the closed surface are negative and those directed out of a closed surface are positive. In this article, the student will learn the Electric flux Formula with examples. Let us learn the concept!
Source:en.wikipedia.org
Electric Flux formula
What is electric Flux?
Consider the flow of water with some velocity v in a pipe in a certain fixed direction, suppose towards the right. We will take the cross-sectional plane of the pipe. Let us consider a small unit area of the plane given as dA. Then the volumetric flow of the liquid crossing that plane normal to the flow will be given as v × dA.
When the plane is not exactly normal to the flow of the fluid then it will be inclined at an angle θ . Then the total volume of liquid crossing through the plane per unit time is given as v×dAcosθ . Here, dAcosθ is the projected area of the plane towards the perpendicular direction of the flow of the liquid.
The electric field is behaving in a similar way. Therefore it is analogous to the flow of liquid as discussed above. If there is no given net charge within some closed surface then every field line directed into the given surface will continue through the interior. The negative flux is just equal to the magnitude of the positive flux. So, the net or total, the electric flux will be zero.
If a net charge is contained within a closed surface, then the total flux through the surface will be proportional to the enclosed charge, i.e. positive if it is positive, negative if it is negative.
The Formula for Electric flux:
The total number of electric field lines passing through a given area in a unit time is the electric flux.
Thus,
Similar to the above example, if the plane is normal to the flow of the electric field, the total flux is given as:
Also, if the same plane is inclined at an angle \theta, the projected area can be given as Acosθ and the total flux through this surface will be,
Where,
| Electric flux | |
| E | The magnitude of the electric field |
| A | Area of the surface |
| The angle between the plane and the axis parallel to the direction of flow of the electric field. |
Solved Examples
Q.1: A planar surface has an area of 1 square meter. If an electric field crosses with an angle of 60∘ to it and has E= 2 Volte per meter. What will be the electric flux?
Solution:
Using the formula of the electric flux,
= 2×1×cos60∘
= 2×1×12
= 1 Volte Meter.
Therefore electric flux will be a 1 Volt Meter.
Energy Formula Physics
Energy is a very important concept in Physics. We can define energy as the strength to do any kind of physical activity. Therefore, we can say that Energy is the ability to do work. Resources are processed to get the energy that is used to provide light or heat for many purposes. We may also compare two persons and concluding that one person has more energy than another person. Thus, we can say that different types of energy can never be created nor destroyed. Also, energy can only be transformed from one form to another form. In this article, we will discuss the concept of energy and energy formula physics with examples. Let us learn the concept!
Source: en.wikipedia.org
Energy Formula Physics
Concept of Energy:
Energy is of mainly two types, Kinetic energy, and Potential energy. Also, there are two forms of energy sources such as renewable sources of energy and Non-renewable source of energy. For example, Renewable sources are solar energy, Wind Energy, and Geothermal energy. On the other hand, Non-renewable sources are Natural gas, Coal and Petroleum products.
The SI unit of energy is Joules (J) which is also termed as Newton-meter. When a certain amount of force in Newton is applied to an object and it moved a certain distance in meters, then the energy applied will be Joules i.e. Newton-meters.
We have to consider potential and kinetic energy in a much detailed way, which are thermal, potential and kinetic energy. Sometimes chemical potential energy is also observed at a broad level. Similar remarks may apply to nuclear potential energy and most other forms of energy.
The formula for Energy:
Kinetic Energy: The energy exists due to the motion of an object is known as Kinetic Energy. For example, a moving van, flowing water, etc.
Where,
| K.E. | Kinetic Energy |
| m | Mass of the object |
| v | The velocity of the object |
Potential Energy: This is the energy stored in an object due to its position and height. It is measured by the amount of work done. For example, a book on a table, water stored in a lake, etc.
Where,
| P.E. | Potential Energy |
| m | Mass of the object |
| g | Acceleration due to gravity |
| h | Height |
Mechanical Energy: It is the sum total of potential energy and kinetic energy which is the energy associated with the motion & position of any object. Therefore, the formula of mechanical energy will be:
Mechanical Energy = Kinetic Energy + Potential Energy
The law of conservation of energy is one of the basic laws of Physics. It states that “In a closed and isolated system from its surroundings, the total energy of the system will be conserved.” Thus energy can neither be created nor destroyed, although it can only be transformed from one form to another.
Solved Examples
Q.1: Calculate the kinetic energy of a 25 kg object which is in the moving state with a velocity of 120 ms−1 .
Solution:
m = 25 kg
Formula for kinetic energy is:
= 12×25×1202
= 25×60×120
= 180KJ
Therefore kinetic energy will be 180 Kilo Joules.
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