MOTION
Motion is any kind of movement. Motion is caused by forces. A still or stationary object does not move unless a force acts on it to start it going. Once it is moving it carries on at the same speed in a straight line unless a force makes it speed up, change direction or slow down and stop.
There are many kinds of movement. An object going in a straight line like a rocket shooting through deep space has linear motion. An object going around a central point like a ball swung around on a string has circular motion. An object moving to and fro like a pendulum has reciprocating motion. An object that twists around like a wheel or a screwdriver has rotary motion.
An object stays still or keeps moving in a straight line, unless forces act on it. A bus will not start to move unless the engine provides a force to make it do so. This tendency of an object’s motion to stay the same is called inertia. Once the bus is moving, the force of air resistance tries to slow it down. The engine keeps the bud going forward. If the bus stops suddenly, people on it fall forward because there is nothing to stop them moving.
Picture Credit : Google
