In this post, we will see the laws of motion of 9th std science 6 lessons online textbook and online reading. let go see...

1. Laws of Motion

The motion of an object

Can you tell? 
In which of the following examples can you sense motion? How will you explain the presence and absence of motion?

1. The flight of a bird
2. A stationary train
3. Leaves flying through the air
4. A stone lying on a hill 

We see the motion of several objects every day. Sometimes we cannot see the motion of an object directly, as in the case of a breeze. Can you list other examples of motion, besides those given here?

Think about it.

1. You are traveling on a bus. Is the person sitting next to you in motion? 
2. What do you take into consideration to decide if an object is moving or not?

You have learned that motion is a relative concept. If the position of an object is changing with respect to its surroundings, then it is said to be in motion. Otherwise, it is said to be at rest.

Displacement and distance

1. Measure the distance between points A and B in different ways as shown in figure 1.1(a) 

2. Now measure the distance along the dotted line. Which distance is correct according to you and why?

1.1 Location of the school and houses

Think about it. 

A. Sheetal first went to her friend Sangeeta’s house on her way to school (see figure 1.1b). 

B. Prashant went straight from home to school. Both are walking at the same speed. Who will take less time to reach the school and why?

In the above example, is there a difference between the actual distance and the distance travelled? What is it?

‘Distance’ is the length of the actual path travelled by an object in motion while going from one point to another, whereas displacement is the minimum distance between the starting and finishing points.