# Accelerated Motion

dx
Homework Helper
Gold Member
Sorry If I wasn't clear. Zach, calculate the distance that the object moves in 1 second from the time it started moving. Then calculate the distance that it moves in 2 seconds from the time it started moving. The difference of these values will give you the distance it moves in the 2nd second, i.e. the distance it moves in the time interval between the 1st second mark and the 2nd second mark.

can you guys see the pic?

malty
Gold Member
can you guys see the pic?

No we can't, try hosting it on imageshack,photobucket etc etc

Not to worry though, we have a good idea as to what you were asked? Just carry out what dx has told you above. My velocities from 1- 5 seconds are as follows: 2 m/s, 4 m/s, 6 m/s, 8 m/s, 10 m/s.
My Distances are as follows: ??

Take a look at the pic!

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malty
Gold Member
My velocities from 1- 5 seconds are as follows: 2 m/s, 4 m/s, 6 m/s, 8 m/s, 10 m/s.

Correct!!

Sorry If I wasn't clear. Zach, calculate the distance that the object moves in 1 second from the time it started moving. Then calculate the distance that it moves in 2 seconds from the time it started moving. The difference of these values will give you the distance it moves in the 2nd second, i.e. the distance it moves in the time interval between the 1st second mark and the 2nd second mark.

Or alternatively use the velocitys for each second, find the distance travelled in that second, do this for all 5 seconds and then add em up. Try doing it the way dx says though because, you wouldn't like to have to the summing for 30 or 40 seconds would you?

One thing: It says that the distance from zero to 2nd second is 4 meters. They also say the distance from zero to one second is 1 meter. So thinking logically I came up with 3 meters for the distance from 1 second to 2 second...Then it asks what the distance is from 2 second to 3 second(s)..then asks from 3 sec to 4 sec (length)..then from 4 sec to 5th sec...HELP!!

malty
Gold Member
As dx and me have been trying to tell you, to get the distance travelled in any one second you merely have to find the total distance travelling in t seconds and the total distance travelled in t-1 seconds.

The distance travelled in the second t will be equal to the [Total distance travelled in (t) seconds]-[Total distance travelled in (t-1) seconds]

E.g take you times to be 1 second and 2 seconds.

In t seconds the total distance travelled from time t=t seconds to t=0 seconds equals
$$d=\frac{at^2}{2}=t^2$$

so:for t=1
$$d_1=\1^2=1$$

and for t=2
$$d_2=2^2=4$$

Thus for the second second, the distance travelled in was:

$$d_(t)-d_(t-1)=d_2-d_1= 4-1$$

EDIT: Dam Capslock :(

Last edited:
can't see what you wrote, can you post again

malty
Gold Member
As dx and me have been trying to tell you, to get the distance travelled in any one second you merely have to find the total distance travelling in t seconds and the total distance travelled in t-1 seconds.

The distance travelled in the second t will be equal to the [Total distance travelled in (t) seconds]-[Total distance travelled in (t-1) seconds]

E.g take you times to be 1 second and 2 seconds.

In t seconds the total distance travelled from time t=t seconds to t=0 seconds equals
$$d=\frac{at^2}{2}=t^2$$

so:for t=1
$$d_1=1^2=1$$

and for t=2
$$d_2=2^2=4$$

Thus for the second second, the distance travelled was:

$$d_{(t)}-d_{(t-1)}=d_2-d_1= 4-1$$

EDIT: Dam Capslock :(

Fixed, sorry bout that :)

Last edited:
So its 3 meters~!~ YA!

from the second second to the third sec:
9-4 =5 metres!

malty
Gold Member
So its 3 meters~!~ YA!

Now, can you tell me what it would be in say the 21st second?

Let's ignore the the incline length, and please don't try to do this by adding each and everyone individually.

More importantly though, do you understand why it is the difference of the two?

From the 3rd second to the fourth.

16 - 9 = 7...right?

individual sec. and total sec. right?

quick q:

4 plus 9 plus 16 plus 9 doesn't equal 25?

malty
Gold Member
quick q:

4 plus 9 plus 16 plus 9 doesn't equal 25?

Well why should it?
I've absolutely no idea what you are adding here.

1+3+5+7+9=25 is what I think you should be adding, this is true isn't it? My math may be rusty :)

hey my bad ur right. Added up wrong things. Thanks so much!!