MOTION Level Middle Students

By Subhash Jain

WHAT IS MOTION? In physics, motion is a change in position of an object

with respect to time and its reference point. Motion is typically described in terms of displacement, direction, velocity, acceleration, and time.

• Start and end position? • Movement relative to what?• How far did it go? And in what direction did it go?

B A20 m 15 m 10 m 5 m 0

20 sec 15 sec 10 sec 5 sec 0 sec

WHAT IS SPEED?Speed is the distance an object travels in a certain amount of time.

To calculate speed, you use the following formula: Total Distance covered

(d)

Speed (v) = -----------------------------------

Total Time taken (t)eg. Suppose the horse ran 20 m in 20 sec. What is the speed of horse?

20 – 0 = 20 m

Speed (v) = -------------------- = 1 m/sec

20 – 0 = 20 sec

GRAPH THE FOLLOWING DATA

00 05 10 15 20

00 05 10 15 20

Distance in meterTime in second

0 5 10 15 20 250

5

10

15

20

25

Time in second

Dis

tance in m

ete

r

VELOCITYVelocity is the speed of an object, but the direction is also included. It is calculated the same as speed, but you must include a direction in your answer.

Example: the bass boat is moving 100 km / h toward the north.

North

Indicate which of the following are velocities:

a. 125 cm/secb. 30 km/h northwestc. 350m/sec northd. 520 km/h