# My son is having difficulty with a problem.

#### Thermal

Unfortunately, I can't help him. The problem is this: a=2d/t(squared). Distance=30 cm. t=.9 seconds.

We're not looking for the answer, just the way to figure it out.

Related Introductory Physics Homework Help News on Phys.org

#### Thermal

He came up with: 1.35 m/s(squared)
Note: m/s is meters/second (squared)

#### mrjeffy321

You are trying to find the acceleration, a?

You have a formula, just substitute in,
a = 2(.3) / (.9^2) = .74 m/s^2

#### gfak25

What is the problem?

#### HallsofIvy

Homework Helper
Thermal said:
Unfortunately, I can't help him. The problem is this: a=2d/t(squared). Distance=30 cm. t=.9 seconds.
gfak25's point is that there is no question in there! you give us a formula, and two numbers. Yes, we can guess, as mrjeffy321 did, that "d" is "Distance", and we are given "t" so maybe the problem is to find a.

In this case, the whole point of the formula is to tell you how find a- That formula says "to find a, multiply the d by 2 (that's the "2d") and then divide by t2." The only "hint" or "way to figure it out we can suggest is "Do It!" Since you tell us that d= 30 cm. and t= 0.9 seconds,
a= (2)(30 cm)/(0.9 s)2.

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving