Football Launch Angle - Horizontal Distance Calculation

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Homework Help Overview

The discussion revolves around calculating the horizontal distance a football travels when kicked at a speed of 20 m/s from ground level at a launch angle of 30 degrees. The context is projectile motion, and participants are exploring the relevant equations and concepts involved in this type of problem.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the nature of the problem as projectile motion and question which equations are applicable. There are attempts to break down the problem into components, such as calculating initial velocities along the x and y axes and determining the time the football is in the air. Some participants express uncertainty about the equations needed and seek clarification on how to derive them.

Discussion Status

There are multiple lines of reasoning being explored, with some participants providing hints and pointers on how to approach the problem. While specific calculations are mentioned, there is no explicit consensus on a single method or equation to use, indicating an ongoing exploration of the topic.

Contextual Notes

Participants are working within the constraints of a homework assignment, which may limit the information they can use or the methods they can apply. There is also a focus on understanding the forces acting on the football in both the x and y directions.

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A football is kicked at 20m/s from ground level. When the launch angle is 30 degrees, the football will travel a horizontal distance of about_____?

would this be projectile motion?

which equation would you use?
 
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Elphaba said:
A football is kicked at 20m/s from ground level. When the launch angle is 30 degrees, the football will travel a horizontal distance of about_____?

would this be projectile motion?

which equation would you use?

Yes,u can think of the ball as a projectile.
HINT:Calculate the intial speed along the 2 axes.Find the time in which the ball is in the air,then use it calculate "x".

Result:Round about 34m.
 
um... what's the equation and how do you get the equation
 
Elphaba said:
A football is kicked at 20m/s from ground level. When the launch angle is 30 degrees, the football will travel a horizontal distance of about_____?

would this be projectile motion?

which equation would you use?

How far have you come?

Here's a few pointers on how you could start to solve the question:

First, draw the problem on a piece of paper. It's a two-dimensional problem, so the x- and y-axis will do.

Divide the forces acting on the footboll into the different axis. First, how large is the force acting in the x-axis? Is there anything preventing this force? Secondly, what forces are acting along the y-axis?

When you have figured out the forces, all you need is to calculate how long it will stay in the air (hint: y=0 will happen twice. When it is kicked, and when it lands).

Use this time to calculate how far the fotball comes in the x-direction.
 
Elphaba said:
um... what's the equation and how do you get the equation

I suppose I'll just display it in easy terms.

Find the initial vertical velocity and the initial horizontal velocity.

horizontal initial velocity = [tex]cos(30) * 20 = 17[/tex]

vertical initial velocity = [tex]sin(30) * 20 = 10[/tex]

since 9.8 is the gravitational acceleration, the projectile should reach the top of the path at 10/9.8 seconds, which is ~1. Since the time from the bottom to the top of the parabola is equal to the time from the top to the bottom, we have to multiply this number by 2, which brings us to ~2. Now we know that t = ~2 seconds, and, so we simply multiply this number by the horizontal initial velocity and we should get the total distance (this is brought about by the equation [tex]x = (v_{ix})(\Delta t) + \frac{1}{2}a_xt^2[/tex], but since there is no horizontal acceleration, the second part of the equation drops out, leaving [tex]x = (v_{ix})(\Delta t)[/tex])

As you can now see, the result is ~34 meters.

So, as for your question, there is no general equation since there are multiple parts to this problem. Instead, there are 3 or 4 that you have to use to find the final result.
 
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