# Urgent Kinematics Help!

## Homework Statement

A car that is accelerating uniformly travels 18 m in the fifth second of its motion.
Calculate acceleration.

I've tried to answer this a million different ways.
If it's in the fifth second on motion that means it has travelled for four seconds, yes?
And I'm not sure that this question gives enough variables for it to be answered... would you agree?

d=ut+0.5(at^2)

## The Attempt at a Solution

The answer in my book says 4.0 is correct. I can't seem to get this.
d=ut+0.5(at^2)
18=0+0.5(16a)
36=16a
36/16
=2.25

Then i was thinking perhaps it has travelled 18 m in 0.5 seconds only, so i did
:d=ut+0.5(at^2)
18=0=0.5(0.25a)
36=0.25
36/0.25
=144

## Homework Statement

A car that is accelerating uniformly travels 18 m in the fifth second of its motion.
Calculate acceleration.

I've tried to answer this a million different ways.
If it's in the fifth second on motion that means it has travelled for four seconds, yes?
And I'm not sure that this question gives enough variables for it to be answered... would you agree?

d=ut+0.5(at^2)

## The Attempt at a Solution

The answer in my book says 4.0 is correct. I can't seem to get this.
d=ut+0.5(at^2)
18=0+0.5(16a)
36=16a
36/16
=2.25

Then i was thinking perhaps it has travelled 18 m in 0.5 seconds only, so i did
:d=ut+0.5(at^2)
18=0=0.5(0.25a)
36=0.25
36/0.25
=144