## Physics question on motion

1. The problem statement, all variables and given/known data
An object that is acclerating uniformly travels 22.5 m in the eighth second of its motion.
a) what is the acceleration of the object?

b) how far does the object travel in 6 seconds?

2. Relevant equations
I'm not exactly sure what equation would be necessary-
perhaps -- a=v-u/t
v=u+at
x=ut+1/2at^2

3. The attempt at a solution

i attempted to use the a=v-u/t equation, however, it wasn't successful. I don't even think you can use that equation since we dont have the values for velocity;initial nor final.
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 Recognitions: Gold Member Homework Help Science Advisor The object has no motion at t = 0. How far does it travel in 8 seconds? How far does it travel in 7 seconds? Its displacement between the. 7th and 8th seconds is given as 22.5 m. Use your last equation.
 Recognitions: Homework Help Hi einstein101. The eighth second is that time difference between seven seconds and eight seconds. travel during first 7 seconds= u.7 + (1/2)a.72 travel during first 8 seconds= ????

## Physics question on motion

But how do I find the initial velocity for the equation?
And how would I exactly go about finding the acceleration?

 Quote by PhanthomJay The object has no motion at t = 0. How far does it travel in 8 seconds? How far does it travel in 7 seconds? Its displacement between the. 7th and 8th seconds is given as 22.5 m. Use your last equation.
It says nowhere that the object started from rest.

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 Quote by e^(i Pi)+1=0 It says nowhere that the object started from rest.
It says "in the eighth second of its motion". I would interpret that to mean that it started from rest.

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 Quote by einstein101 But how do I find the initial velocity for the equation? And how would I exactly go about finding the acceleration?
Can you finish the equation I left uncompleted?

 Quote by Doc Al It says "in the eighth second of its motion". I would interpret that to mean that it started from rest.
Hmm, I suppose you're right.
 so travel during first 8 seconds=u x 8 +1/2(a)(8)^2 then what do i do?

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 Quote by einstein101 so travel during first 8 seconds=u x 8 +1/2(a)(8)^2 then what do i do?
Good. Now subtract that from the companion equation I gave you, viz., of distance travelled during first 7 seconds.

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