Physics

posted by .

I'd like to know when it is appropriate to use each formula. Im new to studying physics and its seems that there are certain situations when one formula leads to the answer, yet a derivative of that formula that should lead to the answer is incorrect.

For example: the question was if i toss a ball in the air, and the Distance =0 (as a ball comes back to the ground and tossed from the ground), Time= 2 seconds, and acceleration = -10m/s^2. What is the initial velocity?

I tried using the Change in Velocity= Acceleration x Time. which should work because i am given acceleration and time. My working out is:


Vfin-Vini = -10m/s^2 x 2seconds
vfin=0 - Vini= -20
vini= 20m/s

But apparently the correct way to answer this question is to use this formula : Change in D= Vinitial x time + acceleration x Time ^2/2. Which works out to be 10m/s

If anyone could please tell me when it is appropriate to use each formula. OR where i have gone wrong in this please let me know

  • Physics -

    The final velocity (after 2 seconds) is not 0. It is zero after 1 second, at the top of the trajectory. That is why you got the wrong answer the first way.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. math derivative please help

    the derivative of 2x^e is zero right or no?
  2. Chemistry

    Please check my answers for the following questions. THANK YOU. 1) The empirical formula of a compound that is 25.9% nitrogen and 74.1% oxygen is.... ANSWER: N2O 2) empirical formula of a compound that consists of 4.80 grams of carbon, …
  3. Re: Finance

    Thanks, Economyst. What formula did you use to calculate 17.53117?
  4. Physics

    The question said find the speed of sound at a certain temperature. What formula would you use?
  5. Physics E=mc^2

    Can you explain what formula (like quadrantic..whatever formula) and what is it for. The equation E=mc^2. Thanx!
  6. Chemistry

    the formula H2O2 is an example of 1.molecular formula 2. an empirical formula 3.an ionic formula 4.an organic formula
  7. Check my physics

    Would you mind checking one of my problems from my physics study guide?
  8. Physics

    Whats the difference between frictionless and friction in a way of solving?
  9. Physics

    On the question that someone posted.....I asked my teacher on what formula I should use and said I should use this one: V^2= Vo^2+2ax (V^2 is the velocit, Vo is the initial velocity, a is accerlation and x distance . An automobile …
  10. Physics

    Why they need to use gravitational constant in the formula?

More Similar Questions