# Rearranging Kinematic Equations. Help.

#### KayAr

1. Homework Statement
2. Homework Equations
3. The Attempt at a Solution

The template doesn't really apply to what I need help with. I've missed some school and I need help rearranging Kinematic equations. I am new to physics so please use plain english.

Here's the specific one I am having problems with, but I need a general rule in order to rearrange them:

Δd = ½a(Δt)^2 (trying to get equation for acceleration.)

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#### Delphi51

Homework Helper
Glad to see you on the physics forums. Welcome!

The general idea is to do the same thing to both sides: add or subtract something, multiply or divide by something. Try to gradually get the variable you are looking for all by itself. Sometimes it is very helpful to ask what has been done to that variable when the formula was created. In this case, your acceleration has been multiplied by 1/2 and by (Δt)^2. To undo these, you divide both sides by 1/2 (or multiply by 2) and divide both sides by (Δt)^2.

Δd = ½a(Δt)^2
2Δd = a(Δt)^2 after multiplying by 2
2Δd/(Δt)^2 = a after dividing by (Δt)^2

#### KayAr

Glad to see you on the physics forums. Welcome!

The general idea is to do the same thing to both sides: add or subtract something, multiply or divide by something. Try to gradually get the variable you are looking for all by itself. Sometimes it is very helpful to ask what has been done to that variable when the formula was created. In this case, your acceleration has been multiplied by 1/2 and by (Δt)^2. To undo these, you divide both sides by 1/2 (or multiply by 2) and divide both sides by (Δt)^2.

Δd = ½a(Δt)^2
2Δd = a(Δt)^2 after multiplying by 2
2Δd/(Δt)^2 = a after dividing by (Δt)^2
Wow, after your explanation it all came back to me.

Thank you Homework Helper
Most welcome!

#### KayAr

is Δt the only thing squared or is it the entire term that it is a part of? if it is only Δt then why is Δt in parentheses?

#### Delphi51

Homework Helper
Only delta t is squared. The brackets make it clear that it is delta t that is squared, not just t.
When you write (x*y*z)^2 it means all of x*y*z is squared as in
x*y*z*x*y*z.

#### KayAr

Only delta t is squared. The brackets make it clear that it is delta t that is squared, not just t.
When you write (x*y*z)^2 it means all of x*y*z is squared as in
x*y*z*x*y*z.
Thanks again

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