RBSE Class 7 Science Notes Chapter 13 Motion and Time

These comprehensive RBSE Class 7 Science Notes Chapter 13 Motion and Time will give a brief overview of all the concepts.

RBSE Class 7 Science Chapter 13 Notes Motion and Time

→ When a body changes its position with respect to time it is said to be in motion.

→ Motion can be along straight line, circular or periodic.

→ The distance moved by objects in a given interval of time can help us to decide which one is faster or slower.

→ The speed is a total distance covered, divided by the total time taken. Thus,
Speed = \(\frac{\text { Total distance covered }}{\text { Total time taken }}\)

→ Periodic events are used for the measurement of time. Periodic motion of a pendulum has been used to make clocks and watches.

→ The time taken by the pendulum to complete one oscillation is called its time period.
Time period = \(\frac{\text { Total time taken }}{\text { Number of oscillations }}\)

→ The basic unit of time is second(s) and the basic unit of speed is metre/sec or m/s.

→ One microsecond is one millionth of a second and one nano second is one billionth of a second. Clocks that measure such small time intervals are used for scientific research.

→ Once you know the speed of an object you can find the distance covered by it in a given time.
Distance covered = speed x time

→ You can also find out the time that an object would take to cover a distance while moving with a given speed.
Time taken = \(\frac{\text { Distance }}{\text { Speed }}\)

→ Speedometer records the speed directly in km/h.

→ Odometer measures the distance moved by the vehicle.

→ Motion of objects can be represented in pictorial form by their distance-time graph.

→ If the distance-time graph is a straight time, it indicates that the object is moving with a constant speed.