VELOCITY AND ACCELERATION


An object is said to be at rest if it doesn’t change its position or move from its position with respect to its surrounding objects.

  • An object is said to be in motion if it changes its position with respect to its surrounding objects.

  • If a body covers equal distance in equal interval of time, it is said to be in uniform motion.

  • If a body covers unequal distance in equal interval of time, it is said to be in variable motion.

  • The quantities which can be measured are known as physical quantities.

  • There are two types of physical quantities. They are:

  1. Scalar quantities

  2. Vector quantities

  • Physical quantities having only magnitude but no direction is known as scalar quantities.

  • Physical quantities having both magnitude and directions known as vector quantities. 

Scalar quantity 

Vector quantity

  1. It has only magnitude.

  1. It has both magnitude and direction.

  • The sum of scalar quantities is always zero.

    • 2.    The sum of vector quantities may be           negative or zero or positive.


    1. They can be added by simple rules of algebra.

    3.  They can’t be added by simple rules of algebra.

    • The actual length of a path travelled by a moving body irrespective of its motion  is called distance.

    • The shortest distance between initial and final position of the moving body in a particular direction is called its displacement.

    Distance 

    Displacement 

    1. The actual length of a path travelled by a moving body irrespective of its motion is called distance.

    1. The shortest distance between initial and final position of the moving body in a particular direction is called its displacement.

    1. It is scalar quantity.


    1. It is a vector quantity.

    1. It is always positive.

    1. It may be positive, negative or zero.

    • The distance travelled by a body per unit time is known as speed.

    • Speed = distance travelledtime taken

    • Velocity can be defined as the distance travelled by body per unit time in a given direction.

    Speed 

    Velocity 

    1. The distance travelled by a body per unit time is known as speed.

    1. The distance travelled by body per unit time in a given direction. 

    1. It is scalar quantity.

    1. It is vector quantity.

    1. It is always positive.

    1. It may be positive, negative or zero.


    • The rate of change of velocity with time is known as acceleration.

    • The negative acceleration is known as retardation or declaration.

    • Point that does not change its position with respect to its surrounding objects is reference point.

    Comments

    Post a Comment

    Popular posts from this blog

    MEASUREMENT

    Image
                                                                             Measurement is the comparison between unknown quantities with known standard quantities. Some of the importance of measurement are: Measurement is important for selling and buying goods in markets. It is essential for doing chemical experiments. It is necessary for doing new inventions. It is important for making laws and rules. Physical quantities are those quantities which can be measured and are countable. For example: height, weight, length, etc. Non-physical quantities are those quantities which cannot be measured and are not countable. For example: love, emotion, anger, ...
    Read more

    SIMPLE MACHINE

    Image
    The device consisting of very few parts that makes work easier, faster or more convenient is called simple machine. Complex machine are formed by combination of many simple machines. Functions of simple machines are : A simple machine is used to overcome a load by applying small force. A simple machine is used to change the direction of force. A simple machine increases the speed of work. Effort is the force applied to the machine. Load is the force applied by the machine to the body. Fulcrum is the support point required to turn or rotate the machine. The distance of effort from fulcrum is effort arm. The distance from fulcrum to load is load arm. The work done on the machine is called input work. Input work = effort × effort arm The work done by the machine on the load is output work . Output work = Load × Load arm The ratio of load overcome by a machine to effort applied in the machine is mechanical advantage. Mechanical advantage =  load effort The velocity ratio of a simple ...
    Read more