# Isn't acceleration a constant?

1. Aug 23, 2007

### chaotixmonjuish

The position of a particle as a function of time (in s) is given by C1 + C2t + C3t2. Let C1 = 12.1 m, C2 = 14.9 m/s and C3 = -0.38 m/s2.

I was able to solve the first question, which was asking for the velocity at T=11.0 seconds. However, I don't understand how to solve this part of the question:

What is the particle's acceleration at time t = 11.0 s?

I thought acceleration was a constant? I tried punching the constant into Lon-capa, but it said the answer was wrong.

2. Aug 23, 2007

### learningphysics

Yes, acceleration turns out to be constant. What number did you get for the acceleration?

3. Aug 23, 2007

### chaotixmonjuish

I got something like -.76 for my acceleration. However Lon-capa rejects it.

4. Aug 23, 2007

### learningphysics

Yeah, -0.76 is the right answer.

Is the question exactly as you posted it?

5. Aug 23, 2007

### chaotixmonjuish

That's is the question.

6. Aug 23, 2007

### learningphysics

Hmmm... I'm not familiar with Lon-Capa... maybe something about the way you entered it? Did you enter it as -0.76 or -.76 ?

Would that make a difference?

I really don't know. :(