 # Kinematics

## 9th Class Physics Chapter 2 Exercise Short Questions with Answers

Q 2.2 : Explain translatory motion and give examples of various types of translatory motion .

Translatory Motion :

” The motion in which a body moves along a line (straight or curved ) without any rotation , is called translatory motion .”

Types of Translatory Motion :

• Circular motion
• Linear motion
• Random motion

1 . Circular Motion :

” The motion of an object in a circular path is known as circular motion .

Example : A car moving along a circular track .

2 . Linear Motion :

” Straight line motion of a body is known as linear motion .”

Example : Aero-plane flying straight in the air is linear motion .

3 . Random Motion :

” The disordered or irregular motion of an object is called random motion .”

Example :Motion of insects and birds is random motion .

Q 2.3 :Differentiate between the following .

i .

ii.

iii.

iv.

v.

vi.

Q 2.4 : Define the term speed , velocity and acceleration .

Speed (v):

” The distance covered by an object in unit time is called its speed .”

Velocity (v) :

” The rate of change of displacement is called velocity .”

Acceleration (a) :

Q 2.5 : Can a body moving at a constant speed have acceleration .

Yes , A body moving at a constant speed have acceleration .

Condition :

If a body is changing its direction then it has acceleration acting towards Centre provided by centripetal force .

Q 2.6 : How do riders in a Ferris wheel possess translatory motion but not rotatory motion ?

Riders in Ferris wheel have circular motion (a type of translatory motion ).

Reason :

• Because their motion is in a circle without rotation .
• And the line about which wheel riders goes around , lies outside the body .

Q 2.7 : Sketch a distance-time graph for a body starting from rest . How will you determine the speed of a body from this graph ?

Q 2.8 : What would be the shape of a speed-time graph of a body moving with variable speed ?

The shape of velocity-time graph is zigzag i.e., not a straight line , when the body is moving with variable speed .

Q 2.9 : Which of the following can be obtained from speed-time graph of a body ?

i . Initial speed

ii . Final speed

iii . Distance covered

iv . Acceleration of motion

All the above quantities can be obtained from speed-time graph of a moving body .

Q 2.10 : How can vector quantities be represented graphically ?

Graphical representation of Vector :

Graphically , a vector can be represented by a line segment with an arrow head .

Q 2.11 : Why vector quantities cannot be added and subtracted like scalar quantities ?

vector quantities cannot be added and subtracted like scalar quantities.

Reason : Vector quantities have direction and quantities having direction cannot be added and subtracted like scalar quantities .

Q 2.12 : How are vector quantities important to us in our daily life ?

Vector quantities are very important to us in our daily life .

• Vector quantities help us to determine position / direction of any place .

Example : Pilots use vectors to detect their destination .

Q 2.13 : Derive equations of motion for uniformly accelerated rectilinear motion .

Q 2.14 : sketch a velocity-time graph for the motion of the body . From the graph explaining each step , calculate total distance covered by the body .

• The area under a speed-time graph represents the distance travelled by the object (i.e. car ) .

Kindly Subscribe my YouTube Channel @Learn with ZahraAwan