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A '''frame of reference''' is a particular [[perspective (visual)|perspective]] from which the [[universe]] is observed. Specifically, in [[physics]], it refers to a provided set of [[Coordinate axis|axes]] from which an [[observation|observer]] can measure the position and motion of all points in a system, as well as the [[orientation (geometry)|orientation]] of objects in it.
A '''frame of reference''' is a particular [[perspective (visual)|perspective]] from which the [[universe]] is observed. Specifically, in [[physics]], it refers to a provided set of [[Coordinate axis|axes]] from which an [[observation|observer]] can measure the position and motion of all points in a system, as well as the [[orientation (geometry)|orientation]] of objects in it.
There are two types of reference frames: [[inertial reference frame|inertial]] and [[non-inertial reference frame|non-inertial]]. An inertial frame of reference is defined as one in which [[Newton's first law]] holds true. That is, one in which a [[free particle]] travels in a [[straight line]] (or more generally a [[geodesic]]) at constant [[speed]]. In three dimensional [[Euclidean space]], using [[Cartesian co-ordinates]], this means that
There are two types of reference frames: [[inertial reference frame|inertial]] and [[non-inertial reference frame|non-inertial]]. An inertial frame of reference is defined as one in which [[Newton's first law]] holds true. That is, one in which a [[free particle]] travels in a [[straight line]] (or more generally a [[geodesic]]) at constant [[speed]]. In three dimensional [[Euclidean space]], using [[Cartesian co-ordinates]].
A non-inertial frame of reference, therefore, is one in which a free particle does not travel in a straight line at constant speed. For example a co-ordinate system centred at a point on the earth's surface. This frame of reference rotates around the centre of the earth which produces a [[fictitious force]] known as the [[coriolis force]].
A non-inertial frame of reference, therefore, is one in which a free particle does not travel in a straight line at constant speed. For example a co-ordinate system centred at a point on the earth's surface. This frame of reference rotates around the centre of the earth which produces a [[fictitious force]] known as the [[coriolis force]].
Frames of reference are extremely important in the realm of physics for describing all types of phenomena. Choosing an appropriate reference frame and co-ordinate system may simplify the solution to a problem enormously. Let us consider for a second a situation which is relatively common in everyday life. Two cars are travelling along a road, both moving at a constant velocity. At exactly 2pm, they are separated by 200 metres. The car in front is travelling at 22 metres per second and the car behind is travelling at 30 metres per second. If we want to find out how long it will take the second car to catch up with the first, there are three obvious "frames of reference" that we could choose.
Frames of reference are extremely important in the realm of physics for describing all types of phenomena. Choosing an appropriate reference frame and co-ordinate system may simplify the solution to a problem enormously. Let us consider for a second a situation which is relatively common in everyday life. Two cars are travelling along a road, both moving at a constant velocity. At exactly 2pm, they are separated by 200 metres. The car in front is travelling at 22 metres per second and the car behind is travelling at 30 metres per second. If we want to find out how long it will take the second car to catch up with the first, there are three obvious "frames of reference" that we could choose.
Firstly, we could observe the two cars from the side of the road. We define our "frame of reference" as follows. We stand on the side of the road right next to the second car at 2pm. We start a stop-clock at the exact moment that the second car passes us. Since neither of the cars are accelerating, we can determine their positions by the following formulae where <math>x_1(t)</math> is the position of car one after time "t" and <math>x_2(t)</math> is the position of car two after time "t".
Firstly, we could observe the two cars from the side of the road. We define our "frame of reference" as follows. We stand on the side of the road right next to the second car at 2pm. We start a stop-clock at the exact moment that the second car passes us. Since neither of the cars are accelerating, we can determine their positions by the following formulae where x_1(t) is the position of car one after time "t" and x_2(t) is the position of car two after time "t".
x_1(t)=x_2(t)=22t + 200
We want to find the time at which <math>x_1=x_2</math>. Therefore we set <math>x_1=x_2</math> and solve for <math>t</math>. i.e.
We want to find the time at which x_1=x_2. Therefore we set x_1=x_2 and solve for t</math>. i.e.
30t=22t+200
:<math>8t = 200 \quad</math>
:<math>8t = 200 \quad</math>
:<math>t = 25 \quad seconds</math>
:<math>t = 25 \quad seconds</math>
[[Category: General Reference]]
[[Category: General Reference]]
[[Category: Secondary Corpus]]
