# Basic physics homework question

1. Sep 10, 2007

### mrthomas

1. The problem statement, all variables and given/known data

Question #1:

Δd=v¹Δt+½a(t)²

Solve for: a

Question #2:

E= ½ m * v²
Solve for: v

2. Relevant equations

Δd=v¹Δt+½a(t)²
v = Δd / Δt
a = v² - v¹ / Δt
v² = v¹ + a * Δt
Δd = (v² - v¹) * Δt
Δd = v¹ * Δt + ½ a ( Δt )²
E= ½ m * v²

3. The attempt at a solution

I'm not sure how to resolve this one.

2. Sep 10, 2007

### learningphysics

Just solve for a in the first equation... just like normal algebra... rearrange the equation etc...

3. Sep 10, 2007

### Staff: Mentor

One needs to be consistent.

This equation assumes constant acceleration, and t would be the elapsed time from application of the acceleration. v1 would normally the initial velocity (or speed) at the reference time, and d would be the distance at time t.

See this - http://hyperphysics.phy-astr.gsu.edu/hbase/mi.html

and

http://hyperphysics.phy-astr.gsu.edu/hbase/mot.html

As learningphysics indicated, one can solve algebraically for the variables or coefficients in terms of variables and other coefficients.

Last edited: Sep 10, 2007