A body travels 200cm in the first 2second and 220 in the next 4second with deceleration. The velocity of the body at the end of the seventh second is?

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A body travels 200cm in the first 2second and 220 in the next 4second with deceleration. The velocity of the body at the end of the seventh second is?

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A body travels 200cm in the first 2second and 220 in the next 4second ...

Let 'u' be the initial velocity and 'a' the acceleration.

So we have the distance formula

s = ut + 1/2 at^2

In first 2 seconds,

s = 200

Put the values in the formula.

200 = u x 2 + 1/2 x a x (2)^2

200 = 2u + 1/2 x 4 x a

200 = 2u + 2a

100 = u + a -----(I)

In next 4 seconds

Let the distance traveled be 'y'

Time = 2+4 = 6 sec

So according to the formula ,

y = u x 6 + 1/2a x (6)^2

y = 6u + 1/2 x 36 x a

y = 6u + 18a ------(ii)

Now we know that 220 cm was traveled in between 2 sec - 6 sec

y - 200 = 220

y = 420

We know y = 6u + 18a (from [ii])

So, 6u + 18a = 420

u + 3a = 70 ------(iii)

Equating (I) and (iii)

-2a = 30

a = -15 cm/s^2

u = 100 - (-15)

u = 100 + 15 = 115 cm/sec

Now we know v = u + at

We have to find the "v" after 7th second

So v = 115 + (-15) x 7

v = 115 - 105

v = 10 cm/sec

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A body travels 200cm in the first 2second and 220 in the next 4second with deceleration. The velocity of the body at the end of the seventh second is? for Class 9 2024 is part of Class 9 preparation. The Question and answers have been prepared according to the Class 9 exam syllabus. Information about A body travels 200cm in the first 2second and 220 in the next 4second with deceleration. The velocity of the body at the end of the seventh second is? covers all topics & solutions for Class 9 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A body travels 200cm in the first 2second and 220 in the next 4second with deceleration. The velocity of the body at the end of the seventh second is?.

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