This time it's a Rocket

The velocity of a rocket is given by the following function:

v ( t ) = 3 t 2 2 t 1. v(t)=3t^2-2t-1.

Find the displacement of the rocket over the time interval ( 1 , 3 ) (1,3) .

Image credit: Wikimedia Commons .


The answer is 16.

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1 solution

Sravanth C.
Mar 21, 2016

We know that the area under the velocity time graph gives us the displacement traversed in that interval. And we know that this is nothing but the integral of the velocity function over that period.

Thus the displacement of the rocket over the time interval ( 1 , 3 ) (1,3) will be:

1 3 3 x 2 2 x 1 d t = [ x 3 x 2 x ] 1 3 = 3 3 3 2 3 ( 1 3 1 2 1 ) = 27 9 3 + 1 = 16 \begin{aligned} \displaystyle\int_{1}^3 3x^2-2x-1 \, dt &=[x^3-x^2-x]_1 ^3\\ &=3^3-3^2-3-(1^3-1^2-1)\\ &=27-9-3+1\\ &=16 \end{aligned}

Thus the displacement of the rocket is 16 m 16m .

Moderator note:

Simple standard approach.

SAme way but its an overrated problem.Pls Change the rating

Kaustubh Miglani - 5 years, 2 months ago

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I don't think this is a complicated question :/

Resha Dwika Hefni Al-Fahsi - 5 years, 2 months ago

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Yep It Isnt

Kaustubh Miglani - 5 years, 2 months ago

I don't know who edited it, I had kept it at level 1 anyways, changed. ;)

Sravanth C. - 5 years, 2 months ago

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