# UBER EASY QUESITON: just need to make sure

1. May 20, 2010

### pfssassin

Just a general question. If you drop a object (air resistance negligible) and you know the t initial is 0 and you know the t final is w/e you get on your stop watch. You do d/t to get average velocity of the fallen object.

Now that you have the avrg velocity you know the V initial is zero and the speed rises to the avrg velocity, can you assume that a = Vavrg/t?

Im in IB physics HL but just cant get my head around this one for some reason....

2. May 20, 2010

### niklaus

Why do you think the speed only rises to the average velocity? If you assume constant acceleration and you had a way to measure the final velocity, then you would be right. But the average velocity would be reached at 1/2 t_final and keep increasing after that...

Out of the data you have (t and d) you can find out a by using $$d = \frac{1}{2} a t^2$$

3. May 20, 2010

### pfssassin

haha wow I feel like an idiot. Thanks.