Describing and Measuring Motion (Describing motion (Motion is when the…
Describing and Measuring Motion
Motion is when the distance between two objects is changing.
A reference point is a place or object used for comparison determine if something is in motion. An object is in motion if it changes position relative to a reference point. Stationary objects are the best for reference points. Some reference points can be moving.
Motion depends on your point of refernece. For example, if you are in a car thats driving, are you moving? Technically the car is moving so it depends on your point of reference.
The International System of Units is the measuring system scientists all over the world use. Measuring distance is measuring length.
If you know the distance an object travels in a certain amount of time, you can calculate the speed of the object. The speed of an object is the distance an object travels over a period of time.
The speed equation
speed = distance/time.
The speed of most moving objects is not constant. To calculate the average speed, divide the total distance traveled by the total time. This is average because you may be going 5 miles per hour at one point in a race and then a hill approaches and you're going 3 mph.
instantaneous speed is the rate at which an object is moving at a given instant time.
You can show the motion of an object on a line graph in which you plot distance versus time. The steepness of a line is called the slope. The steeper the slope, the greater the speed.
You calculate the slope of a line by dividing the rise by the run. Slope = rise/run
Most moving objects do not travel at a constant speed. Many slopes are different.
when you know both the speed and direction of an object's motion, you know the velocity of the object. Speed in a given direction is called velocity.