# NCERT Solutions for Class 9 Science Chapter 8

NCERT Solutions for Class 9 Science Chapter 8 Motion answers of all pages like Intext Questions on Page 100, Page 102, Page 103, Page 107, Page 109 and Exercises in English Medium free to download for new academic session 2021-22. These Solutions are useful for Uttar Pradesh High School Students also. So, download UP Board Solutions for 9 Science chapter 8 here in Hindi Medium. The videos related to each chapters are also available to free download. Hindi Medium version of 9th Science chapter 8 Page 110 ke Uttar, Page 112 ke Uttar, Page 114 ke Uttar, Page 118 ke Uttar, Page 121 ke Uttar and Abhyaas Ke Uttar are given to study online or download in PDF format.

NCERT Solutions 2021-22 for Class 9 all Subjects based on Latest CBSE Syllabus 2021-2022 are available to free download. Download Class 9 offline Apps from Play Store for offline use.

## NCERT Solutions for Class 9 Science Chapter 8

• ### Class 9 Science Chapter 8 Answers in PDF Format

 Class: 9 Science Chapter 8: Motion

### 9th Science Chapter 8 Answers in English & Hindi Medium

CBSE NCERT Solutions for Class 9 Science Chapter 8 Motion all Intext Questions with exercises questions answers free to download or use online. All the solutions are in updated form for current academic session 2021-22. Download Class 9 Science App in Hindi and English Medium for offline use.

### Extra Questions on 9th Science Chapter 8

##### Define speed and velocity. What are their SI units?

Speed: Speed of a body is defined as the distance travelled by the body in unit time.
Velocity: Velocity of a body is the distance travelled by the body in unit time in a given direction.
The SI unit is meter/second.

3 m/s ; zero

(a) 750 m ;
(b) 12.5 m.

(i) 1/15 m/s² ;
(ii) 3 km

10 seconds

##### What type of motion of tips of second’s hand of a watch? Is it uniform or accelerated?

The motion of the tip of second’s hand of a watch is not a uniform motion. It is accelerated motion due to change in the direction of motion.

##### What is the nature of the distance-time graph for uniform and non-uniform motion of an object?

When the motion is uniform, the distance-time graph is a straight line with some slope.
When the motion is non-uniform, the distance time graph is not a straight line. It can be any curve.

##### What is locomotion?

Locomotion is the ability of an animal to move its whole body from place to place without any external forces.

#### Questions for Practice on 9th Science Chapter 8

Question 1:
A train travels 100 m long moving on a straight level track passes a pole in 5 s. Find (a) the speed of the train (b) the time it will take to cross a bridge 500m long.
(a) 20 m/s
(b) 30 s

Question 2:
A car accelerates uniformly from 18 km/h to 36 km h/ in 5 second. Calculate (i) the acceleration and (ii) the distance covered by the car in that time.
1 m/s² ; 37∙5 m

### Important Questions on 9th Science Chapter 8

##### An athlete completes one round of circular track of diameter 200 m in 40 sec. What will be the distance covered and the displacement at the end of 2 minutes 20 sec?

Time taken = 2 min 20 sec = 140 sec. Radius, r = 100 m. In 40 sec the athlete complete one round. So, in 140 sec the athlete will complete = 140 ÷ 40 = 3.5 round. ⇒ Distance covered in 140 sec = 2πr × 3.5 = 2 × 22/7 × 100 × 3.5 = 2200 m. At the end of his motion, the athlete will be in the diametrically opposite position. ⇒ Displacement = diameter = 200 m.

##### When will you say a body is in (i) uniform acceleration? (ii) non-uniform acceleration?

(i) A body is said in uniform acceleration when its motion is along a straight line and its velocity changes by equal magnitude in equal interval of time.
(ii) A body is said in non-uniform acceleration when its motion is along a straight line and its velocity changes by unequal magnitude in equal interval of time.                            