Kinematic Problem: MJ & SP Meet - Find Distance

In summary, the problem involves MJ and SP falling from a tall building with different initial velocities and finding the distance where they meet. The equations for final velocity and displacement are used to find the final position of MJ after 1.5 seconds and this is then used as the initial position for MJ in a new equation. The correct approach is to write separate equations for the position of MJ and SP and use the fact that both start from the same point.
  • #1
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Homework Statement


MJ falls from rest from a tall building. 1.5 seconds later SP throws himself downward with an initial velocity of -45 meters per second. Find the distance where they meet.
variables:
α1= -9.81 α2=-9.81
Δγ1 = ? Δγ2=?
Δ†1=? Δ†2=? + 1.5
∨i1=0 ∨i2=-45
∨f1=unknown ∨f2=unknown

Homework Equations


vf=vi+aΔt (distance is absent)
Δγ=viΔt+½αΔt^2 (final velocity is absent)

The Attempt at a Solution


I think I have the problem right. I found the final velocity and distance where MJ would be after the 1.5 seconds. then I used that final velocity as the initial velocity for MJ. and used that distance as MJ's starting distance. then I used true statements to say the accelerations are the same in both equations, the times are the same in both equations (since I changed my initial velocity and distance) and My distance for spiderman - 11.04 (what I got for the initial distance of MJ) equals MJ's distance. then I used Δγ=viΔt+½Δt^2, and set it up as
11.04=vi1Δt1+½αΔt1^2-vi2Δt2+½αΔt2^2. since I knew my times and accelerations were the same, I knew subtracting ½αΔt2^2 from ½αΔt1^2, leaving me with 11.04=Vi1Δt1- Vi2Δt2. I then subtracted the initial velocities because the times are the same. Then I divided 11.04 by what I got. Would this way give me the correct answer?
 
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  • #2
Man, I though the problem was talking about Michael Jordan and Scottie Pippen!

You should remember that MJ (Michael Jordan or Mary Jane) are still falling after 1.5 sec (and accelerating, no less), so your static approach to finding the time MJ and SP are at the same distance from the top of the building requires a different approach. Try writing separate equations which describe the position of MJ and SP separately, using the fact that both start from the same point.
 

1. How do you calculate distance in a kinematic problem?

In a kinematic problem, distance can be calculated using the formula: distance = velocity x time. This formula applies to both MJ and SP's movements, and the resulting values can be added together to find the total distance traveled.

2. What is the difference between distance and displacement in kinematics?

Distance refers to the total length of the path traveled, while displacement refers to the straight-line distance between the starting and ending points. In this problem, it is important to keep track of both distance and displacement as MJ and SP are moving in different directions.

3. How do you find the velocity of an object in a kinematic problem?

Velocity can be calculated by dividing the total distance traveled by the time it took to travel that distance. In this problem, we can use the total distance calculated earlier and divide it by the total time taken for both MJ and SP to travel to find their average velocity.

4. How does acceleration affect the distance traveled in a kinematic problem?

Acceleration is the rate of change of velocity, and it affects the distance traveled by increasing or decreasing the speed of the object. In this problem, if MJ and SP have different accelerations, it will affect their individual distances and the total distance traveled together.

5. Can you use kinematics to solve for the time taken to travel a certain distance?

Yes, kinematics equations can be used to solve for the time taken to travel a certain distance. In this problem, we can use the formula: time = distance / velocity to find the time taken for MJ and SP to meet at a certain distance.

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