TIMES MODULE M35 - Proportion
Learn about and revise ratio, proportion and rates of change with this BBC Bitesize GCSE Maths Edexcel study guide. These relationships often turn out to be either linear or hyperbolic. If R is a constant, I is directly proportional to V. If V is a constant, I is inversely proportional to R. In the module, Rates and Ratios, the formula d = vt connecting is proportional to the square of the time travelling. Here is a table of values for this situation. How much you earn is directly proportional to how many hours you work It is also possible to be proportional to a square, a cube, an exponential, or other.
Hence, the intensity of radiation passing through any unit area directly facing the point source is inversely proportional to the square of the distance from the point source.
Gauss's law is similarly applicable, and can be used with any physical quantity that acts in accordance with the inverse-square relationship.
Gravitation[ edit ] Gravitation is the attraction between objects that have mass. The gravitational attraction force between two point masses is directly proportional to the product of their masses and inversely proportional to the square of their separation distance.
The force is always attractive and acts along the line joining them. If the distribution of matter in each body is spherically symmetric, then the objects can be treated as point masses without approximation, as shown in the shell theorem.
Inverse Square Law, General
Otherwise, if we want to calculate the attraction between massive bodies, we need to add all the point-point attraction forces vectorially and the net attraction might not be exact inverse square. However, if the separation between the massive bodies is much larger compared to their sizes, then to a good approximation, it is reasonable to treat the masses as a point mass located at the object's center of mass while calculating the gravitational force. As the law of gravitation, this law was suggested in by Ismael Bullialdus.
Indeed, Bullialdus maintained the sun's force was attractive at aphelion and repulsive at perihelion. Hooke's Gresham lecture explained that gravitation applied to "all celestiall bodys" and added the principles that the gravitating power decreases with distance and that in the absence of any such power bodies move in straight lines.
ByHooke thought gravitation had inverse square dependence and communicated this in a letter to Isaac Newton: There are examples where conversion of units does not involve direct proportion, such as converting Fahrenheit to Centigrade. Conversely, the radius of a circle is directly proportional to the circumference of the circle. From science The mass of a body is proportional to its volume. The constant of proportionality is the density of the body.
The constant of proportionality is the mass.
- Inverse Square Law Formula
- Direct and inverse proportion
- Inverse Proportion and The Hyperbola Graph
The constant of proportionality between the mass and the force is known as gravitational acceleration. For a constant force acting on a body, the work done by the force is proportional to the distance through which the body moves.
BBC Bitesize - GCSE Maths - Direct and inverse proportion - Edexcel - Revision 3
The proportionality constant is the product of the mass and gravitational acceleration. For a body moving in a circle with constant angular speed, the linear speed tangential speed is proportional to the angular speed.
The constant of proportionality is the radius of the circle. The weight of the displaced fluid is directly proportional to the volume of the displaced fluid. In simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object.
At constant pressure, the volume V of a given mass of an ideal gas increases or decreases by the same factor as its temperature T on the absolute temperature scale i. The properties of direct proportion can be usefully applied in each of the examples above.
Here are two other important examples.