Question

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Answer 1

EXPLANATION:-

GIVEN:-

Speed time graph of cyclist

TO FIND:-

Acceleration at particular time period

STEP BY STEP ACCELERATION:-

(1) Acceleration from 0-10 s

We know that :-

$\sf\;acceleration=\frac{final\;velocity-initial\;velocity}{time}\\\\\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;or\\\\a=\frac{v-u}{t}$

So in the time interval of 0-10 second :-

Final velocity=15 m/s

Initial velocity=0 m/s

Time taken=10 sec

So acc =(15-0)/10

Acceleration=1.5 m/s

$\rule{200}{5}$

(II)In the time interval of 10-15 second:-

Final velocity =10 m/s

Initial velocity=15 m/s

Time taken=5 second

So acc=(10-15)/5

Acceleration=-5/5

Acceleration=-1 m/s   [MEANS RETARDATION]

$\rule{200,5}$$\rule{200}{5}$

(III) In the time interval of 15-20 second:-

Final velocity=25 m/s

Initial velocity=10 m/s

Time taken=5 second

Acc=25-10/5

Acceleration=15/5

Acceleration= 5 m/s

$\rule{200}{5}$

(IV) In the time interval of 20-40 second

Since the graph is a straight line so the velocity is constant so the acceleration=0