Euqation of kinematics in two dimensions

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Homework Help Overview

The discussion revolves around a kinematics problem in two dimensions, specifically evaluating the claim about Michael Jordan's jump duration and maximum height. Participants are analyzing the motion of an object under the influence of gravity, focusing on the initial velocity and height calculations.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the use of kinematic equations to find the initial velocity and maximum height. There is confusion regarding the time duration of the jump and how it relates to the upward and downward motion. Questions arise about the correct interpretation of the total flight time and its implications for calculations.

Discussion Status

Some participants have offered guidance on clarifying the motion's phases, suggesting that the total time of two seconds should be split into ascent and descent. There is an acknowledgment that using the correct values for each part of the motion is crucial for accurate calculations. However, no consensus has been reached on the exact values or methods to apply.

Contextual Notes

Participants are working under the constraints of a homework problem, which may limit the information available for solving the kinematics scenario. The discussion includes assumptions about the jump's duration and the effects of gravity.

pookisantoki
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Fans claim that Michael Jordan is able to jump and remain in the air for two full seconds from launch to landing. Evaluate this claim by calculating the maxium height that such a jump would attain. For comaprsion, Jordan's maximum jump height has been estimate at about one meter.
Y=1meter
t=2second
Ay=-9.80
Vy=0
Voy??

I used Vy=Voy + Ay*t
0=Voy+-9.8 *2
Voy=19.6

But it's wrong...not sure what to do from here...
 
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I used Vy=Voy + Ay*t
0=Voy+-9.8 *2
Voy=19.6

This is very close, but you have to be careful to be clear on what part of the motion you are working with. The 2 seconds is for the full flight - up and down. A final velocity of 0 is for half the flight - just the up part. Choose one or the other for all quantities and you'll get your answer!

Since you are interested in finding the height, you might prefer to use a distance formula. You'll need to find the initial velocity first if you tackle the "up" part with the distance formula, but if you do the down part you of course know the initial velocity.
 
So that would just make Voy 9.8...?
 
Yes.
 

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