- Books Name
- Science Made Easy Science Book
- Publication
- Science Made Easy
- Course
- CBSE Class 9
- Subject
- Science
Frame of Reference - A frame of reference is another object or scene with respect to which we compare an object's position.
Objects changing positions with time with respect to the frame of reference are in motion while those which do not change position are at rest.
For example – A passenger sitting on a moving bus is at rest with respect to his co-passenger but at the same time, he is moving with the bus with respect to a person standing outside.
Scalar quantities
The quantities that depend upon magnitude and not the direction is called scalar quantities. They are represented as their own symbol.
Vector quantities
A physical quantity that depends upon magnitude as well as direction. They are represented by putting on their symbol.
Distance and Displacement:
Distance
• The distance travelled by a moving object is the length of the path the object takes.
• The measure of distance is a scalar quantity. The meter is the SI unit of distance.
Displacement
• It is the shortest path covered by a moving object in a specified direction from the point of reference (the initial position of the body).
• The meter is the SI unit of displacement.
• Displacement is a vector, which means that it is represented by a number with appropriate units and direction.
Difference between Distance and Displacement
Distance |
Displacement |
Distance provides the complete details of the path taken by the object |
Displacement does not provide the complete details of the path taken by the object |
Distance is always positive |
Displacement can be positive, negative or zero |
It is a scalar quantity |
It is a vector quantity |
The distance between two points may not be unique |
The displacement between two points is always unique |