# Help dont know where to start

1. Nov 22, 2004

### tman

An object falls because of gravity at a rate of -980 cm/sec2 (- sign is indicative of a downward direction) for 10 seconds. If it starts from rest (vo= 0) and its position starts from do= 0, where is it 10 seconds later?

_______________m

I don't know where to start

Last edited: Nov 22, 2004
2. Nov 22, 2004

### tman

maybe use d=1/2vt but what do I plug in

3. Nov 22, 2004

### arildno

Whatever is this??

You have constant acceleration, how is distance as a function of time given in that case?

4. Nov 22, 2004

### Raza

I think it is 980m

5. Nov 22, 2004

### tony873004

If every second, it is moving 980 cm / second faster, then how fast is it going in 10 seconds?

v = a * t

what is its average velocity during this 10 second peroid? Hint: It started at 0, it ended at a*t. Take the average.

Now distance is easy. It travelled an average velocity for a known time.

This formula is wrong.
d = vt

Following the logic above, you should be able to come up with the correct formula for d using a (acceleration) instead of v (veolcity).

This is wrong too. How did you get this? Watch your units. You expressed acceleration in cm, but your answer in meters, which is ok to do, but make sure you convert properly.

Last edited: Nov 22, 2004
6. Nov 22, 2004

### phreak

Just use this formula

$$\Delta x = \frac{1}{2}at^2$$

Input the values and solve. -4.9m(100s)

-490 meters from its original position

Last edited: Nov 22, 2004
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