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.

 

[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]

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.