Murder Mystery Solution using Kinematic Equations

In summary, the conversation is about a student seeking help with a physics problem involving a murder mystery story. They have provided important information from the story, including the victim and suspects' details and the kinematic equations needed to solve the problem. The student shares their attempt at solving the problem and expresses their struggle with their first physics class. They also mention their need for guidance in the right direction.
  • #1
kstategirl121
1
0
I'm new to this site, so let me know if I'm doing anything wrong.

Homework Statement


I have attached the original problem in a PDF file. I have to read a murder mystery story and pull information from it to plug into kinematic equations and find out who commited the murder.

Important information that I have pulled out of the story:
--No air resistance
--Each room is has a 14ft high ceiling with 2 feet between each floor.
--Bloodstains are 18ft from the entrance to the building
Victim:
1. Adam Able. 5'11. 160 lbs.

Suspects:
1. Adrianna Myers (Room 356)
2. Steven Caine (Room 852)
3. Mark Johnson (Room 1956)
4. Stanley Michaels (Room 2754)


Homework Equations


Kinematic Equations:
1x. V=Vo+at
2x. X=Xo+1/2(V+Vo)t
3x. X=Xo+Vot+1/2at^2
4x. V^2=Vo^2+2a(X-Xo)

1y. Y=Vo+at
2y. Y=Yo+1/2(V+Vo)t
3y. Y=Yo+Vot+1/2at^2
4y. V^2=Vo^2+2a(Y-Yo)

Xo & Yo = Initial Position
X & Y = Final Position
Vo = Initial Velocity
V = Final Velocity
A = Acceleration
T = time


The Attempt at a Solution


Knowing that each floor is 16ft total, I use the person's room number to find out high up the are. I know that in the end I need to figure out how high up Adam fell from and compare that to the suspects rooms to know who killed him. Note: I've also converted everything to meters

The first thing I did was solve for time using the x-axis equations.
Xo=0
X= 5.4864 m (18ft where bloodstains were)
Vo = 0 m/s
V = 2 m/s (You'll notice in the attached file that our teacher gives a hint stating that if we were in lab and pushed our partner hard, we'd find that they'd have a speed of 2 m/s)
a = ?
t = Find!
I plugged all of this into Equation 2x and got 5.864 seconds. (I believe this is wrong after going further, I'm just explaining what I did.

The second thing I did was plugged in the time to find out Yo.
Yo = Find!
Y = 0 m
Vo = 0m/s
V = ?
a = -9.81 m/s (Gravity)
t = 5.4864 s
I plugged this into Equation 3y and got 25.24 m. This is seeming way off.

I know this is long. This is a take-home problem for my exam tomorrow. I'm not asking anyone for answers. I just need help going in the right direction. This is my first physics class ever and its turning out to be way harder than I expected and I have no friends takign classes like mine.
 

Attachments

  • Take Home Problem.pdf
    876 KB · Views: 410
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  • #2
For the horizontal motion, Adam's initial velocity will be about 2m/s and there will be no acceleration in the horizontal direction after he's shoved. It looks like your equation 3x would be the better choice, setting a to zero.
 

1. How do kinematic equations help solve a murder mystery?

Kinematic equations, which are based on the principles of physics, help determine the position, velocity, and acceleration of objects. By analyzing the movements of suspects and victims using these equations, investigators can piece together a timeline of events and identify potential culprits.

2. What are the main kinematic equations used in a murder mystery investigation?

The four main kinematic equations used in a murder mystery investigation are displacement (Δx = v0t + ½at2), velocity (v = v0 + at), acceleration (a = Δv/t), and time (t = Δx/v). These equations relate the variables of displacement, velocity, acceleration, and time to each other.

3. Can kinematic equations be used to determine the exact location of a murder?

While kinematic equations can help narrow down the location of a murder, they cannot determine the exact location. Other factors such as environmental conditions, human error, and the presence of other objects can affect the accuracy of these equations.

4. How can kinematic equations be used to rule out suspects in a murder case?

If the movements of a suspect do not match the calculated movements based on the kinematic equations, they can be ruled out as a potential culprit. This can help investigators narrow down their list of suspects and focus on individuals whose movements align with the equations.

5. Are there any limitations to using kinematic equations in a murder mystery investigation?

Kinematic equations rely on certain assumptions, such as constant acceleration and no external forces acting on the object. In a real-life scenario, these assumptions may not always hold true, leading to potential errors in the calculations. Additionally, human error and other factors can also affect the accuracy of these equations.

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