How to Calculate Position at 8 Seconds Using Kinematic Equations?

In summary, the conversation is about finding the position at 8 seconds using the equation X = ½ at² + vt + x. The initial values are given as -34m, -3m/s, and -4.0m/s2. The conversation also includes a discussion about using two equations to find the position at the end of 2 seconds and the remaining 6 seconds. The final calculation for the position at 8 seconds is -138m, but it is not correct and the individual is seeking help to find where they went wrong in their calculation.
  • #1
rodjav305
10
0

Homework Statement



I have put the diagram in an attachment. I need to find position at 8 seconds.

Homework Equations



X = ½ at² + vt + x

The Attempt at a Solution



-34m + (-3m/s)(8.0s)+ ½ (-4.0m/s2)(1.0s)2 = -165 meters
 

Attachments

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  • #2
You have to find the position and the velocity at the end of 2 s and then find position at the end of 8 seconds. ( i.e. in the remaining 6 s.)
 
  • #3
How would I go upon doing that? A couple of people told me to use two equations
 
  • #4
Up to 2 s,

x1 = xo + vo*t1 + 1/2*a*t1^2

v1 = vo + a1t1

For remaining 6 s,

x2 = x1 + v1*t2 + 1/2*a2*t2^2
 
  • #5
hmmmm this is what i just did for x2

x2= (-42m) + (-4m/s)(6.0s)+ 1/2(-4.0m/s^2)(6.0s)^2 = -66m + (-72m) = -138m

It still gives me a wrong answer...can you explain where i went wrong?
 

1. What is position at 8 seconds?

Position at 8 seconds refers to the location or coordinates of an object at a specific time point, which in this case is 8 seconds.

2. How is position at 8 seconds calculated?

Position at 8 seconds is calculated by using the formula: position at 8 seconds = initial position + (velocity x time). This equation takes into account the object's initial position and its velocity at 8 seconds to determine its final position.

3. Why is it important to find position at 8 seconds?

Finding position at 8 seconds is important in many scientific fields, such as physics and engineering, as it allows us to track the movement and trajectory of objects. This information can be used to make predictions and calculations for various purposes.

4. What factors can affect the accuracy of finding position at 8 seconds?

The accuracy of finding position at 8 seconds can be affected by factors such as errors in initial position and velocity measurements, external forces acting on the object, and the assumptions made in the calculation.

5. How can the accuracy of finding position at 8 seconds be improved?

To improve the accuracy of finding position at 8 seconds, it is important to use precise and accurate initial position and velocity measurements, consider and account for any external forces acting on the object, and minimize any assumptions made in the calculation.

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