Establish the formula v = u + at and s = ut + 1 2 at 2 where symbols have usual meaning.

We know that acceleration is defined as the rate of change of velocity. a = Change in velocity time = v - u t at = v - u v = u + at → 1 Where , u - initial velocity , v - final velocity , a - acceleration , t - time When a body having initial velocity u is acted upon by a uniform acceleration a for time t , the final velocity of the body is v and distance covered is s . The average velocity is given by the arithmetic mean of initial velocity and final velocity for a given period of time. The distance covered = Average velocity × time s = u + v 2 × t Substituting for v from eq. ( 1 ) s = u + ( u + at ) 2 × t = 2 u + at 2 × t s = ut + 1 2 at 2

E M B I B E

Core Science Physics For Class 9>Chapter 1 - Motion>EXERCISE>Q 4

EASY

9th CBSE

IMPORTANT

Earn 100

Name a physical quantity corresponds to :

(a) rate of change of displacement (b) rate of change of velocity.

Important Questions on Motion

EASY

9th CBSE

IMPORTANT

Core Science Physics For Class 9>Chapter 1 - Motion>EXERCISE>Q 5

Give an example of a body moving with a uniform speed and uniform acceleration. Justify your answer.

MEDIUM

9th CBSE

IMPORTANT

Core Science Physics For Class 9>Chapter 1 - Motion>EXERCISE>Q 1

By giving one example each, define: (a) uniform velocity, (b) variable velocity and (c) average velocity.

MEDIUM

9th CBSE

IMPORTANT

Core Science Physics For Class 9>Chapter 1 - Motion>EXERCISE>Q 2

A motorcyclist drives from A to B with a uniform speed of

30 km h^{- 1}

and returns back with a speed of

20 km h^{- 1}

. Find its average speed in

km h^{- 1}

MEDIUM

9th CBSE

IMPORTANT

Core Science Physics For Class 9>Chapter 1 - Motion>EXERCISE>Q 3

A body starts from rest and moves along the x-axis with constant acceleration $5 m s^{- 2} for 8$ seconds. If it then continues with constant velocity. What distance (in metre) will the car cover in $12$ seconds since it started from the rest?

(Write only the magnitude of the answer in the given box)

MEDIUM

9th CBSE

IMPORTANT

Core Science Physics For Class 9>Chapter 1 - Motion>EXERCISE>Q 4

How will the equations of motion for an object moving with a uniform velocity change?

MEDIUM

9th CBSE

IMPORTANT

Core Science Physics For Class 9>Chapter 1 - Motion>EXERCISE>Q 1

Establish the formula