Introduction |
Gravitation
Conten * Universal law of gravitation * Kepler’s law * Acceleration due to gravity * Mass, Weight * Thrust, Pressure * Pressure in fluid * Buoyancy or Upthrust * Archimedes’s principle * Density * We always feel that an object dropped from a height falls towards the earth. We known that all the planets go around the sun. the moon goes around the earth. In all the situation, there must be some force acting on the objects, the planets and moon. Isaac Newton given that the same force is responsible for all these. This force is known as gravitational force. We are going to study about gravitation in details.Universal law of gravitationEvery object in the universe attracts every other object with a force which is proportional to the square & inversely proportional to the square of the distance between them. This is called gravitation force & given by the formula F = G- ( i ) Here ‘M’ and ‘m’ is the mass of two objects A and B are separated distance ‘d’ from each other as shown in fig and G is called Universal gravitation constant
Also, G = – ( ii ) The SI unit of gravitation constant is Nm2kg-2and the accepted value is 6.673 *10-11
Nm2 kg -2
Note: Gravitational force always along the line joining the centries of two objects. * Kepler’s law Johannes Kepler de three laws, which are related to the motion of planets. These laws given as 1. The orbit is a planet is an ellipse with the sun at one of the foci as shown in fig (2).
The Essay on Biomechanics Of Tennis Force Ball Object
Bio-mechanical Principles of the Serve Bio-mechanics is the science that looks at the internal and external factors acting on the human body and the effects produced by these factors. Bio-mechanics studies what makes a body move and the results of that movement. The two main principles of the tennis serve are motion and force. Motion is the "continued change of position of an object in space" ...
Here o is the position of the sun.Figure 2 Sun of one of the foci –– 2. The line joining the planet and the sun sweeps equal areas in equal intervals of time. 3. The cube of the mean distance of the planet from the sun is proportional to the sugar of its orbital period T.or= constant * Acceleration due to gravity is acceleration due to the gravitational force of earth. It is represented by ‘ g’ and unit of it same as that of acceleration i.e. (ms -2 ),. * By second law of motion, we can writeF = mg
Here M is the mass of earth, and d is the distance between the object and the earth. Equation (3) shows that for objects for from the earth, the acceleration due to gravitational force. * An object be on or near the surface of the earth, the distance d will be equal to R, the radius of the earth, then- ( iv ) Or- ( v )
Note: The radius of the earth increasing from the poles to the equator, the value of g becomes greater at the poles than at the equator. * The value of the acceleration due to gravity of the earth, g = 9.8 ms-2 * Mass is quantity of object is contain in object, it is constant and does not change from place to place. * Weight of an object is the force with which it is attracted towards the earth it is denoted as W and given asW = m x g The SI unit of weight is same as that of force, i.e., Newton (N).
The weight is a force acting vertically downwards; it has both magnitude and direction.
Note:The mass of an object remains the same everywhere, that is, on the earth and on any planet whereas its weight depends on its location. * The weight of an object on the moon is the force with which the moon attracts that object. The mass of the moon is less than that of earth..due to this moon exerts lesser force of attraction on object.. * The weight of an object on moon is given asHere, Mm and m is the mass of the moon and the mass of an object respectively and Wm and Mm are weight of the moon and radius of the moon respectively. * The weight of the same object on the earth be We. The mass of the earth is M and its radius is R, given as
The Essay on Measuring The Density Of Pennies
1. The equation that relates density, mass, and volume is: density = mass / volume. 2. All substances have unique densities, so if you are able to find the density of a substance, you can properly identify it. 3. We measure irregular-shaped objects with the use of water displacement because it would be nearly impossible to get the exact measurements of items with irregular shaped surfaces ...
Note: The weight of the object on the moon is equal to 1/6 its weight on the earth. * Weight is the force acting vertically downwards, and the force acting on an object perpendicular to the surface is called thrust. The thrust on the unit area is called ‘pressure’, i.e.The SI unit of pressure is called ‘Pascal’ (Pa) or Nm-2
Pressure in fluidsAll liquids and gases are fluids. A solid exerts pressure on a surface due to its weight. Similarly, fluid have weight, and they also exerts pressure on the base and walls of the container in which they are enclosed. Pressure exerted in any confined mass of fluid is transmitted undiminished in all directions. * Buoyancy or upthrust is the upward force exerted by the water on the object when it is immersed in fluid. The magnitude of the upthrust force is depending on the density of the fluid. * Archimedes’s principle, starts that when an object is immersed fully or partially in a fluid, it experience that upwards force that is equal to the weight of the fluid displaced by it. * Lactometers are based on Archimedes principle, which are used to determine the purity of the sample of milk and hydrometers used to determine density of liquids.Thedensityof an object is defined as mass of a unit volume. The unit of density is kilo gram per meter cube (kgm-3).
The density of an object is one of its characteristic properties. The relative density of an object is the ratio of its density to that of water. i.e.
It has no unit, because it a ratio of similar quantity
Note: The density of given sample of an object can help us to determine its purity. The density of gold is 19300kgm-3. The density of water is 1000kgm-3.
Points to remember * In solar system, all the planets go around the sun. * The straight line that meets the circle at one and only one point is called a tangent of the P Q R circle, as shown in figure. Straight line PQR is the tangent to the circle at point Q. * The law is universal in the sense that it is applicable to all bodies, whether the bodies are * big or small, whether they are celestial or terrestrial. * Whenever objects fall towards the earth under the gravitational force alone, we can say that the object are in free fall. * Gravitation is a weak force unless large masses are involved. * Objects having density less than that of the liquid in which they are immersed, low on the surface of the liquid. If the density of an object is more than the density of the liquid in which it is immersed than it sinks in the liquid. |
The Essay on Objects Speed Velocity Time Distance
Time (s) Distance (m) Displacement (m) Velocity (m / s ) 0. 5 0. 06 0. 02 0. 1 1 0. 115 0. 012 0. 06 1. 5 0. 176 0. 021 0. 105 2 0. 232 0. 018 0. 09 2. 5 0. 289 0. 026 0. 13 3 0. 355 0. 034 0. 17 3. 5 0. 405 0. 032 0. 16 4 0. 47 0. 025 0. 125 4. 5 0. 55 0. 3 1. 5 1. Initial velocity is the speed and direction in which the object is moving at the beginning of a time interval and final velocity is ...
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Introduction |
Content * Speed, Velocity * Acceleration * Graphical representation of motion * Equations of motion * Uniform circular motion
Motion * In our daily life, we can see some objects at rest and some in motion. Atoms, molecules, planets, stars and galaxies are all in motion when its position with time. Most motions are complex. Some objects may move in a straight line, others may take a circular path. * Motion of an object describe by the distance and the displacement, and to locate its final position with reference to its initial position at a given time. * A motion is said to be uniform motion, if an object covers equal distances in equal intervals of time. * A motion is said to be non-uniform motion, if an object covers unequal distances in equal intervals of time. * For measuring the rate of motion of an object is to find out the distance travelled by the object in unit time.This quantity is referred as speed * The SI unit of speed is meter per second (ms-1).
The other units of speed are centimetre per second (cms-1) and kilometre per hour (kmh-1).
To specify the speed of an object, we need only its magnitude. * In most cases, objects will be in non-uniform motion, so we describe the rate of motion of such objects in terms of their average speed. The average speed of an object is obtained by dividing the total distance travelled by the total time taken. i.e.Average speed =If an object travels a distance s in time t then its speed v is v = s/ t
Note:To specify the speed of an object, we require its magnitude not its direction * The rate of motion of an object can be more comprehensive if we specify its direction of motion along with its speed. The quantity that specifies both these aspects is called velocity. Velocity is the speed of an object moving in a definite direction. * The velocity of an object can be uniform or variable, it can be changed by changing the object’s speed, direction of motion or both. If an object is moving along a straight line at a variable speed, we can express the magnitude of its rate of motion in terms of average velocity. * In case the velocity of the object is changing at a uniform rate, then average velocity is given asAverage velocity =orWhere Vav is the average velocity, u is the initial velocity and v is final velocity of the object The unit of velocity is also same as speed i.e. ( ms-1) * Accelerationis a measure of the change in the velocity of an object per unit time, It is represented by (a)i.e.
The Essay on Object Travels Time Rock Video
After successfully completing the first two videos of the Paul Hewitt series, I have been drawn to this course. The third video of the series reviews the concepts of vectors and projectiles. In this video Paul goes over a lot of previously stated formulas. The ideas of how fast or hoe far an object travels are restated. The idea of how fast an object travels is known as its velocity. The velocity ...
If the velocity of an object changes from an initial value u to find value v in time t, the acceleration a is
The acceleration is taken to be positive if it is in the direct ion of velocity and negative when it is opposite to the direction of velocity. The SI unit of acceleration is ms-2
Note:Acceleration is said to be uniform acceleration when its velocity changes at a uniform rate, and said to be non-uniform acceleration when its velocity changes at a non-uniform rate.
Graphical representation of motionGraphs gives a convenient method to present basic information about a variety of events . To describe the motion of an object, we can use line graphs. In this case, line graphs show dependence of one physical quantity such as distance or velocity and time * The change in the position of an object with time can be represented on the distance-time graph. In this graph, time is taken along the x-axis and distance is taken along the y-axis as shown in figure (1)
* Distance-time graph can be employed under various conditions where objects move with uniform speed, non-uniform speed, remain at rest etc. * We can use the distance-time graph to determine the speed of an object. In the graph, AC denotes the time interval (t2-t1) while BC correspondence to the distance (S2-S1).
Thus the object moves from the point A to B, it covers a distance (S2-S1) in time (t2-t1).
The speed of object can be given as * The variation in velocity with time for an object moving in a straight line can be represented by a velocity-time graph, In this graph, time is taken along the x-axis and the velocity along the y-axis as shown in graph (2)
Figure 2 velocity – time graph ––
* If the object moves at uniform velocity, the height of its velocity-time graph will not change with time. It will be a straight line parallel to the x-axis. * Since the product of velocity and time give displacement of an object moving with uniform velocity. The area enclosed by velocity-time graph and time axis will be equal to the magnitude of the displacement.Note:In the case of non-uniformly motion, velocity-time graphs can have any shape * If an object moves along a straight line with uniform acceleration, it is possible to relate its velocity, acceleration during motion and the distance covered by it a certain time interval by a set of equations known as the equation of motion. These equations are given asV = u + at …..(1) S = ut + 1/2at2 ….(2) 2 as = v2 – u2…..(3) Here u is the initial velocity of the object which moves with uniform acceleration a for time t, v is the final velocity, and S is the distance travelled by the object in time t * If an object moves in a circular path with uniform speed, its motion is known as uniform circular motion. * If an object takes t second to go one around the ircle path of radius r, the velocity is given as
The Essay on A Favorite Place I Like To Spend Time
A Favorite Place I Like to Spend Time Sometimes, when I feel tired and exhausted, I need a place for relaxation. Although there are many places, where one can feel relaxed, such as reading in a library with a cup of coffee, or sitting in a comfortable chair, covered with a cozy warm rug, holding a cup of fresh hot tea with scents of flowers, herbs, and jasmine and looking through the window, where ...
Points to remember * The motion of an object could be uniform or non-uniform depending on whether its velocity is constant or changing. * The magnitude of the displacement for a course of motion may be zero but the corresponding distance covered is not zero. * Uniform and non-uniform motions of object can be shown through graphs. * The rate of change of velocity is known as acceleration. |
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