Grade 9 Physics – Motion in One Dimension Numericals Part 1 with Answers

Motion in One dimension

Numericals Part:1

Question:1

The speed of a car is 72 km/h. Express it in meter per second.

Given:
Speed of the car = 72 km/h

Conversion:
1 km = 1000 m
1 hour = 3600 s
Therefore,
1 km/h
= 1000/3600 m/s
= 5/18 m/s

Formula:
Speed in m/s = Speed in km/h × 5/18
Substitution:
= 72 × 5/18
Calculation:
72 ÷ 18 = 4
4 × 5 = 20
Answer:
Speed of the car = 20 m/s

Question:2
Express 15 m/s in kilometer per hour.

Given:
Speed = 15 m/s

, Conversion:
1 m/s = 18/5 km/h

Formula:
Speed in km/h = Speed in m/s × 18/5
Substitution:
= 15 × 18/5
Calculation:
15 ÷ 5 = 3
3 × 18 = 54
Answer:
15 m/s = 54 km/h

Question : 3A
Express 10 km/h in meter per second.

Given:
Speed = 10 km/h

Conversion:
1 km/h = 5/18 m/s

Formula:
Speed in m/s = Speed in km/h × 5/18
Substitution:
= 10 × 5/18
Calculation:
10 × 5 = 50
50 ÷ 18 = 2.77
Answer:
10 km/h = 2.77 m/s