Physics: Projectile Motion - Maximizing Soccer Ball Distance/Hang-Time

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Homework Help Overview

The discussion revolves around a physics problem related to projectile motion, specifically focusing on maximizing the distance and hang-time of a soccer ball. Participants are analyzing the effects of initial velocity and launch angle on the projectile's range and time of flight.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss various equations related to projectile motion, including expressions for distance and time of flight. Some express uncertainty about their answers and seek clarification on the reasoning behind different choices. Others question the mixing of horizontal and vertical components in their calculations.

Discussion Status

The conversation is ongoing, with participants providing insights and corrections to each other's reasoning. Some have suggested looking up specific formulas, while others have pointed out the implications of certain assumptions. There appears to be a productive exchange of ideas, though no consensus has been reached on the correct answer.

Contextual Notes

Participants are working within the constraints of a homework assignment, which may limit the information available for discussion. There is also mention of the problem being part of an SAT question, indicating potential limitations in the diagram's accuracy.

  • #31
Harenderjeet Arora said:
TIme of Flight= 2v0sinθ/g and Horizontal Range=v02sin2θ/g
Looking at both the equations, it's easily concluded that by increasing v0 both Time of Flight and Horizontal Range will increase.
Not the tricky part is with θ.
For the given value of v0, Horizontal Range at θ and 90°-θ are equal although the time of flight is different. Why?
Because in the equation of Horizontal Range, we have sin2θ and you can check that value of sin2θ for θ=30° and θ=60° are same. Hence if v0 is also constant, then Horizontal Range for θ=30° and θ=60° will be same. So it's now clear that increasing θ will not increase Horizontal Range forever.
So out of the options present, I'll put my money on Option. C

You’re definitely right. I was finally able to recognize this at the end. Thank you all for your efforts...
 
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  • #32
Harenderjeet Arora said:
TIme of Flight= 2v0sinθ/g and Horizontal Range=v02sin2θ/g
Looking at both the equations, it's easily concluded that by increasing v0 both Time of Flight and Horizontal Range will increase.
Not the tricky part is with θ.
For the given value of v0, Horizontal Range at θ and 90°-θ are equal although the time of flight is different. Why?
Because in the equation of Horizontal Range, we have sin2θ and you can check that value of sin2θ for θ=30° and θ=60° are same. Hence if v0 is also constant, then Horizontal Range for θ=30° and θ=60° will be same. So it's now clear that increasing θ will not increase Horizontal Range forever.
So out of the options present, I'll put my money on Option. C
We much prefer to help students figure out the answers rather than providing them with a full solution.

By the way, I would have preferred for the OP to realize that when we plot ##\sin(2 \theta)## from 0 to 90 degrees (the range of possible angles ##\theta##), the value of ##\sin(2 \theta)## increases as ##\theta## goes from 0 to 45 degrees but then actually decreases as ##\theta## goes from 45 to 90 degrees. So as long as the angle is below 45 degrees, we gain in range by increasing it, but past 45 degrees, we start losing in range. So the optimum angle for the range is 45 degrees. This is was I was aiming at with my guiding questions.
 
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  • #33
nrqed said:
We much prefer to help students figure out the answers rather than providing them with a full solution.

You certainly made me able to figure out the solution. Thanks a million.
 
  • #34
nrqed said:
We much prefer to help students figure out the answers rather than providing them with a full solution.
I am sorry, I didn't know. Just joined the Forum now, will keep that in mind.
 
  • #35
Harenderjeet Arora said:
I am sorry, I didn't know. Just joined the Forum now, will keep that in mind.
No problem at all! Your help will be appreciated by many students I am sure. I just wanted to give you an idea of how we work here since you just joined us. And welcome!
 
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