Chapter 13: Motion and Time
One of the most well-known periodic motions is that of a simple pendulum. In everyday life we seldom find objects moving with a constant speed over long distances or for long durations of time. If the speed of an object moving along a straight line keeps changing, its motion is said to be non-uniform.
Slow and fast moving objects
We already know that a moving object shows three kinds of motion, the rectilinear motion, the circular motion and the periodic motion. But how do we know whether the motion is slow or fast? This we decide by seeing the speed with which an object moves. Now, what is speed? A very common word for movement, speed designates the rate of change in position. Before discussing speed lets discuss the varying levels of motion. You might have seen bullock carts, cars, scooters, and bicycles moving. How do you tell which one shows slow motion and which one shows fast motion? The answer here is simple, you compare them and their change in positions with regard to time. When all of these vehicles move in the same direction, we accurately know which one is moving faster.