Physics deals with the things around us and we find it everywhere in our lives. Kinematics is a big part of physics! Recently we learned about velocity (how a velocity vs. time graph works) and acceleration. Velocity is the speed of an object in a given direction. Acceleration is the increase in the rate of something. We also learned the two other graphing rules:
1. The slope of a position v. time graph is velocity.
2. The slope of a velocity v. time graph is acceleration.
3. The area under the curve of a velocity v. time graph is displacement.
When driving to school, we need to get out of the valley to get onto the freeway. The speed limit on our roads in the valley is about 25 mph. When we approach the freeway, we start to accelorate our speed. While driving on the freeway, we stay at a constant speed of about 50 mph (speed limit 50). Getting off of the freeway, we decelerate to about 25 mph until we get to school.
Even though we are constantly moving while driving, it doesn't mean we are constantly accelerating. When we are driving it off the valley, we are going at a constant speed of 25 mph. On a graph, this would have a slope of zero because we are not accelorating, but staying constant. At the start of the onramp to the freeway until we get onto the freeway, there would be a positive slope on our velocity v. time graph because we are increasing our acceloration. On the freeway we would be at a constant speed of 50 mph (slope 0). Getting off of the freeway, we would slow down, causing our slope to go in a negative direction. On the final stretch to school, our slope would be zero because we would be traveling at a constant 25 mph.
Physics is all around us!
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