Question

A particle starts from rest with uniform acceleration a. Its velocity after n seconds is v. The displacement of the particle in the last two seconds is

Answer 1

so what is the question?

Answer 2

I forgot to add "is" _-_

Answer 3

can you phrase it in a question? I mean even 3-year-olds can ask proper questions

Answer 4

What, this is asked appropriately. Clean your eyes nincompoop

Answer 5

haha he forgot the "is"

Answer 6

wear some eye lenses

Answer 7

eyes have lens

Answer 8

artificial

Answer 9

so do you know what is being asked?

Answer 10

Ok no.name where are you stuck? In these kinds of equations we are generally looking for what is known and we can find that by simply listing what is known. So list your known variables and equations.

If you have two variables and two unknowns, you're probably on the right track.

Answer 11

Keep in mind, displacement is technically two unknowns combined into one slightly vague unknown.

Answer 12

average velocity in the last 2 seconds times 2 seconds?

Answer 13

that last two seconds is bothering me somehow

Answer 14

why?

Answer 15

We have
x(t) = 1/2*a*t^2 + vi*t

Answer 16

dx/dt = at + vi , when t = 2 we have a(2) + vi = v ,

Answer 17

if you can solve it without it being 2 seconds, then you can solve with it

Answer 18

\[s_{n-2}=\dfrac{1}{2}a (n-2)^2 = \dfrac{1}{2}a(n^2 - 4n + 4)\]\[s_{n}=\dfrac{1}{2}an^2\]\[s_n - s_{n-2} = \dfrac{1}{2}a(4n - 4) = 2a(n-1)\]\[v = an \Rightarrow 2an - 2a =\boxed{ 2(v - a)}\]

Answer 19

If the answer is 2(v - a) then I can explain.

Answer 20

oh cool!