1 of 9

�NAVODAYA VIDYALAYA SAMITI�(An Autonomous Body Under MHRD) Government Of India �

Presents

E-Content for Class VII (Science)

2 of 9

Chapter 13

MOTION AND TIME

-Developed by

Mr. Vinod Kumar

T.G.T. Science

J. N. V. Dibrugarh, Assam

3 of 9

NAME OF ACTIVITY-� To Know the Time Period of a Simple Pendulum�

REQUIREMENTS- Metallic bob or Small stone, String or thread, Stop watch or Wrist watch

THEORY- A simple pendulum has a string and a bob suspended from any rigid point. It is used to calculate the time period.

PROCEDURE-

A simple pendulum of length 1m (100 cm) was firmly suspended from a rigid point. The bob is taken at one of extreme position away from the mean position of simple pendulum and released carefully without pushing. The number of oscillations completed in 20 seconds was recorded.

4 of 9

��Rigid Support Rigid Support

A Simple Pendulum Different Positions of the bob of

an oscillating simple pendulum

5 of 9

SIMPLE PENDULUM & STOP WATCH

6 of 9

The experiment is repeated 3 times. The time period of each oscillation can be calculated by dividing the total time with 20 i.e. number of oscillations we have assumed to be completed in each case.

S.N. of Experiment	Time taken to complete 20 Oscillations (in s)	Calculation	Time Period ( in s)
1.	44 s	44 s/ 20	2.2 s
2.	56 s	56 s/ 20	2.8 s
3.	68 s	68 s/ 20	3.4 s
4.

Fourth experiment is for you.�CONCLUSION- The measurement of time period of an oscillation can be done by dividing total time taken in completing 20 oscillations (supposed). �

7 of 9

NAME OF ACTIVITY- To measure the speed�

REQUIREMENTS – A ball, Measuring tape and Stop watch or Wrist watch

THEORY- Speed is the ratio of distance to the time. Speed =Distance/ Time. It’s unit is m/s.

PROCEDURE- The ball was moved on a flat surface having marking of the length. In each case the distance covered before stoppage and time taken was noted. By the formula of speed, the speed was calculated.

8 of 9

S.N. of Activity	Distance covered by the ball (in m)	Time taken (in s)	Speed=distance/Time taken = m/s
1.	4.2 m	8 s	4.2m/8s =0.52 m/s
2.	3.8 m	6 s	3.8 m/6s=0.63 m/s
3.

Third activity is for you.

9 of 9

THANK YOU