This lesson will help you to:-
- learn about motion.
- learn about factors that causes a body to be in motion.
- study different types of motion.
- learn about uniform motion, non-uniform motion and circular motion.
Real Life Examples
- When a baseball player runs around the bases, his or her position changes, which shows that motion is performed.
- When you switch on the fan it starts moving in a circular motion.
- Sir Isaac Newton was the one who first thought about the reason why all objects fall down and found the actual reason behind it. He said that gravitational force causes every object to come down. He later found the relationship between force and motion and introduced the three laws of motion.
QUICK CONCEPT REVIEW
The world is filled with movements. Some movements (motion) just happen. The earth revolves around the sun, snowflakes fall to the grounds etc. Some motions we can control, like we walk, pickup things, play etc.
- Motion is a state of change. It is an act, process or instance of changing place.
- It can be a movement caused by nature or a change of location or energy created by manmade means.
- For example when we move our legs to walk, we are putting them in motion.
- Whether the movement is of a planet revolving or you playing a game, the motion happens because of force.
FORCE AND MOTION
- When we push or pull something, we are using force to try to move it or put it into motion.
- For example pushing a table. Pulling a door. Walking etc.
TYPES OF MOTION
There are three types of motion viz. Uniform motion, non-uniform motion and circular motion.
A body is said to be in uniform motion if it covers equal distance in equal interval of time.
- Planets move around the sun in uniform motion.
- Suppose a bus travels at a constant speed of 73 miles per hour. Then this constant speed can be called as uniform motion.
Non- Uniform Motion
- When a body covers unequal distance in equal interval of times or vice- versa, then the body is said to have non-uniform motion.
- For example a racing horse, swing.
- Circular motion is a movement of an object along a circular path or a circular orbit.
- Motion along a circle with constant speed is called uniform circular motion.
- For example highway curves are parts of circles so a car taking a turn is undergoing circular motion.
- There is no gravity in space.
- A football player uses force to run, kick, pass, and tackle when he kicks the football, the speed and direction of the football changes and the shape of the football changes temporarily, too.
Misconcept: Things fall because you let them go, but to go up you have to push them up.
Concept: Gravitational force works on all objects. Any object that goes up is attracted back towards the Earth due to the strong gravitational Force.
Misconcept: If an object is at rest, no forces are acting on the object.
Concept: Even when an object is at rest, there are forces acting upon it.
Misconcept: An object that moves has the ability to do so by itself
Concept: An object moves when any force (push or pull) is acted upon it.