Page 118 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key

written. This gives us the odometer reading for the distance covered by the vehicle

in km.
3. What do you mean by the statement, ‘car is moving with the speed of 50 km/h’?
Ans: This statement means that the car travels 50 km distance in every I hour.

4. Differentiate between uniform motion and non-uniform motion.
Ans: Uniform motion: A body is said to be in uniform motion if it travels equal distances
in equal intervals of time. For example, a car moving at a speed of 20 m/s covers 20

m in every second, then the motion is said to be uniform.
Non-uniform motion: A body is said to be in a non-uniform motion if it travels

unequal distances in equal intervals of time. For example, a freely falling body or a
car moving at a speed of 20 m/s in the first hour and 30 m/s in the following hour.
5. Differentiate between distance and displacement.

Ans: The actual length of the path covered by a moving body is called distance. The
shortest possible distance covered by a body between its initial and final positions is

called displacement.
Displacement is always the straight line path between the initial and final points of
the motion. While stating displacement, it is essential to state the direction of the

motion. Distance is the total length irrespective of its direction.
6. Give an example of oscillatory motion.
Ans: An example of an oscillatory motion is a swing moving back and forth.

7. Arun moves 3 km towards north and then takes a turn and moves 4 km towards east.
Calculate the distance and the displacement of Arun.

Ans:
N According to questions,
4 km
C B
W S
3 km

S
A
Total distance covered by Arun

= 3 km + 4 km = 7 km
Total displacement = AB, which can be calculated as follows, [By Pythagoras Theorem]

(AB) = (AC) + (BC) 2
2
2
or (AB) = (3) + (4) = 9 + 16 = 25
2
2
2
or (AB) = 25
2
or AB = 5 = 5
or AB = 5 km.

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