This slide is based on inventions and about time , speed and motion

1. TIME SPEED
AND
MOTION

2. MOTION
• The movement of an object is called motion.
• An object is said to be in motion (or moving) when its
position changes with time.
• Some example are :
i. A tree is fixed at a place so we say that it is stationary.
ii. A car is moving so we say that it is in motion.

3. TYPES OF MOTION
• Rectilinear motion : motion which follows a straight linear
path is called rectilinear motion.
Examples :
i. a girl walking .
ii. A car moving in a straight path.

4. b. Circular motion : when an object moves in a circular path it is
called as circular motion.
Examples :
i. Movement of moon around the earth.
ii. Revolution of Earth.
c. Rotational motion : motion of circular path on a fix axis.
Examples :
i. Rotation of earth.
ii. Movement of a tyre of a bicycle.

5. d. Periodic motion : the motion which repeats itself after a
regular interval of time is called periodic motion.
Examples :
i. Movement of an pendulum.
ii. Phases of moon.
e. Oscillatory motion : The to and fro motion is called as
Oscillatory Motion.
i. Motion of a swing.
ii. Movements of atoms in molecules.

6. SLOW AND FAST MOTION
when an object works fast or when an object functions at a high
speed it is said to be fast motion. When an object
works/functions at a slow speed it is said to be slow motion.
For examples , car A moves at a high speed at a particular
distance but car B , the same object moves slowly at the same
distance . So this example says that car A is at fast motion but car
B is at slow motion.

7. MOTION

8. SPEED
•The distance covered by an object in unit time
is called its speed. Objects are said to be in
fast or slow motion depending upon the
speed of their motion.
•EXAMPLE : an object moves 4km of speed in
½ hour.

9. PENDULUM
• A small metallic bob suspended by a light inextensible string from a rigid support, such that it is free to
oscillate without friction about a point, is called a simple pendulum.
• Mean Position: When a freely suspended pendulum is at rest, then this position of the bob is called
mean position or rest position.
• Extreme Position: The position of the bob at the maximum distance from the mean position is called
extreme position. There are two extreme positions on either side of the mean position.
• Length of the Pendulum: The distance between the point of suspension to the centre of gravity of the
bob is called the length of the pendulum.
• Oscillatory Motion: The bob of the pendulum moves to and fro along the same path and passes through
the mean position. This type of motion is called oscillatory motion.
• Oscillation: The complete to and fro motion of the pendulum constitutes one complete oscillation.
• Amplitude: The maximum displacement of the pendulum, i.e., the displacement between the mean
position and the extreme position, is called its amplitude.
• Time Period: The time taken by an oscillating pendulum to make one complete oscillation is called its
time period.
• Frequency: The number of oscillations made by the pendulum in one second is called its frequency of
oscillation. The unit for frequency in the SI system is the hertz (Hz).

10. LAWS OF PENDULUM
• There are three laws that govern the time period of a simple pendulum.
• The first law states that the period of oscillation of a simple pendulum of constant
length is independent of its amplitude, provided the amplitude is small.
• The second law states that the period of oscillation of a simple pendulum of
constant length is independent of the size, shape, mass and material of the bob,
provided it is not very light.
• The third law states that the time period of oscillation of a simple pendulum is
directly proportional to the square root of the length of the pendulum, for a given
place.

11. DISCOVERY OF PENDULUM
There is an interesting story about the discovery that the time period of a given
pendulum is constant. You might have heard the name of famous scientist
Galileo (A.D. 1564 –1642). It is said that once Galileo was sitting in a
church. He noticed that a lamp suspended from the ceiling with a chain was
moving slowly from one side to the other. He was surprised to find that his
pulse beat the same number of times during the interval in which the lamp
completed one oscillation. Galileo experimented with various pendulums to
verify his observation. He found that a pendulum of a given length takes always
the same time to complete one oscillation. This observation led to the
development of pendulum clocks. Winding clocks and wristwatches were
refinements of the pendulum clocks.

12. TIME PERIOD
• The time period varies directly with the square root of the length of the pendulum, i.e., T ∝ √l.
• The time period varies inversely with the square root of the acceleration due to gravity, i.e. T ∝ √(1/g).
• From the above T ∝ √(l/g).
• It has been found experimently that the time period of a freely oscillating pendulum is given by
• T = 2π√(l/g)
• where l is the length of the pendulum and g the acceleration due to gravity at a given place. From this
expression, it is clear that as the length of the pendulum increases, its time period increases too.

13. SECONDS PENDULUM
•A pendulum which has a time period of
two seconds is called a second's
pendulum. The length of a second's
pendulum is 1 m and its frequency is 0.5
Hz.

14. FORMULA OF SPEED

15. TYPES OF SPEED
• Uniform Speed - When the object travels a fixed distance same
time gaps, it is said to have a uniform speed.
• Non-uniform speed - When an object covers different distances in
different time gaps, it is said to have a non-uniform speed.
• Average speed - The total distance travelled by an object divided
by the total time taken by the object is called its average speed

16. SPEEDOMETER AND
ODOMETER
•The instrument used in vehicles to
indicate speed is called the speedometer.
The distance covered by a vehicle is
indicated by the odometer.

17. SI UNIT
•The SI unit of time is second (s) and that for
distance is metre (m). So the SI unit of speed is
metre per second (m/s). Speed is also measured in
kilometre per hour (km/h). The average speed of a
moving object is defined as the total distance
covered by it divided by the total time taken.

18. TIME
• There are many events in nature that repeat after a time interval:
• Morning – The rising of the sun
• Day and Night – The time between the sunrise and sunset
• Month – The time between two new moons
• Year – The time the earth takes to complete its one revolution around the sun

19. ANCIENT INSTRUMENTS
TO MEASURE TIME
•Time measuring devices or clocks - Clocks use
the concept of periodic motion to measure
time. It means that it uses motion that repeats
itself in equal amounts of time. There are
different types of time measuring devices.

20. SUNDIAL
• A sundial is a device that tells the time of day when there is sunlight by the apparent
position of the Sun in the sky. In the narrowest sense of the word, it consists of a flat
plate (the dial) and a gnomon, which casts a shadow onto the dial.
STRUCTURE OF A SUNDIAL SUNDIAL

21. SAND CLOCK
• A Sand clock or sand timer or hourglass is a device used to measure the passage of
time. It consists of two glass bulbs connected vertically by a narrow neck that allows
a flow of sand from the upper bulb to the lower one.
• The specific duration of the time is determined based on the amount of sand the
neck allows and size of the bulb.