Deriving the 4th equation of motion

In summary, the conversation discusses how to derive the 4th equation of motion, v2= v02+2aD, from the second and third equations, t=(v-v0)/a and D=1/2at2+v0t, respectively. It is suggested to solve for t in the second equation and substitute it into the third equation to eliminate time. The resulting equation is D=1/2a((v-v0)/a))2+v0((v-v0)/a), which can be simplified by distributing the terms. The conclusion is reached that the correct form of the equation is dependent on the term hooked to 1/2a.
  • #1
danksnaks
2
0
1. All I need to do is derive the 4th equation of motion being v2= v02+2aD from the second (t=(v-v0)/a) and third (D=1/2at2+v0t).
2. In this case D= (Ending-initial distance) V0= Initial Veolocity
3. By having the second equation solved for t I could substitute it in an completely eliminate time and I end up with D=1/2a((v-v0)/a))2+v0((v-v0)/a). Past this point I knwo to distribute the terms, but I have no idea what the correct forms look like because I always ended up with a slight different in the term hooked to 1/2a. Any help here?
 
Physics news on Phys.org
  • #2
I lied. I figured it out.
 
  • #3


I understand your question and I can provide some guidance on how to derive the 4th equation of motion.

First, let's start with the second equation of motion, t=(v-v0)/a. We can rearrange this to solve for v, giving us v=v0+at.

Next, we can substitute this expression for v into the third equation of motion, D=1/2at^2+v0t. This gives us D=1/2a(v0+at)^2+v0(v0+at).

Expanding the terms and simplifying, we get D=1/2a(v0^2+2v0at+a^2t^2)+v0^2+av0t.

Now, we can combine like terms and factor out a v0, giving us D=1/2a(v0^2+2av0t+a^2t^2)+v0(v0+at).

Finally, we can rearrange this equation to solve for v^2, giving us v^2=v0^2+2aD. This is the 4th equation of motion that you were looking for.

I hope this explanation helps and clarifies the steps needed to derive the 4th equation of motion. Remember, it's important to practice and work through the equations to fully understand them. Keep up the good work!
 

1. How is the 4th equation of motion derived?

The 4th equation of motion, also known as the velocity-time equation, is derived using calculus and the principles of motion. It is derived by taking the derivative of the 3rd equation of motion, which is the displacement-time equation, with respect to time.

2. What is the significance of the 4th equation of motion?

The 4th equation of motion is significant because it relates the velocity of an object to its initial velocity, acceleration, and time. It allows us to calculate an object's velocity at any given time during its motion.

3. Can the 4th equation of motion be used for all types of motion?

Yes, the 4th equation of motion can be used for all types of motion, whether it is linear, circular, or projectile motion. As long as the acceleration remains constant, this equation can be used to calculate an object's velocity.

4. How does the 4th equation of motion differ from the other equations of motion?

The 4th equation of motion differs from the other equations of motion in that it involves the variable of time. The other equations only involve displacement, velocity, and acceleration.

5. Are there any limitations to using the 4th equation of motion?

Yes, the 4th equation of motion has limitations when it comes to non-uniform or changing acceleration. It can only be used when acceleration is constant, and it becomes less accurate when dealing with non-constant acceleration.

Similar threads

  • Introductory Physics Homework Help
Replies
13
Views
947
  • Introductory Physics Homework Help
Replies
11
Views
1K
  • Introductory Physics Homework Help
Replies
6
Views
900
  • Introductory Physics Homework Help
Replies
2
Views
3K
  • Introductory Physics Homework Help
Replies
2
Views
767
  • Introductory Physics Homework Help
Replies
6
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
15
Views
1K
  • Introductory Physics Homework Help
Replies
6
Views
1K
  • Introductory Physics Homework Help
Replies
7
Views
2K
Back
Top