Projectile motion football kick problem

In summary, the problem involves finding the least and greatest angles of elevation for a football kicker who can kick the ball with an initial speed of 25 m/s. The goal is located 50m in front of the goalposts, with a horizontal bar 3.44m above the ground. The equations used to solve the problem are: V0tcosX = 50 and V0tsinX - 0.5gt^2 = 3.44. The solution involves finding t in terms of X and using that to find the zeros of the equation y = x*tanθ - (g/2*V0^2)*x^2*(1 + tan^2θ), where g is the acceleration
  • #1
Cherrybawls
18
0

Homework Statement


A football kicker can give the ball an initial speed of 25 m/s. what are the least and greatest angles of elevation at which he can kick the ball to score a field goal from a point 50m in front of the goalposts whose horizontal bar is 3.44m above the ground?


Homework Equations


I really don't know what to do


The Attempt at a Solution


I figured I could write
V0tcosX=50
and
V0tsinX-.5gt2=3.44

Then I tried to find t in terms of X and got
t=50/(V0cosX)

Then I plugged that into the other equation and I got
50tanX-12250/cos2X-2150=0

I thought then I could find the zeros and that would be my answer but it doesn't seem to be working... I can't figure out why. Maybe I totally missed the answer but either way I still need help lol. Thanks.
 
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  • #2
you can write the equation of the projectile as
y = x*tanθ - (g/2*u^2)*x^2*sec^2(θ)
Put sec^2(θ) = 1 + tan^2(θ) and solve the quadratic for tanθ.
 
  • #3
I am confused, what are you referring to with u?
 
  • #4
Sorry. u is Vo.
 

1. What is projectile motion?

Projectile motion is the motion of an object through the air that is affected by gravity. This type of motion is commonly seen in sports such as football, where the ball is kicked and travels through the air before reaching its target.

2. How does projectile motion affect a football kick?

When a football is kicked, it follows a parabolic path due to the combination of its initial velocity and the force of gravity. This means that the ball will travel in a curved path and eventually reach the ground due to the pull of gravity.

3. What factors affect the distance of a football kick?

The distance of a football kick is affected by several factors, including the initial velocity of the kick, the angle at which the ball is kicked, air resistance, and the force of gravity. These factors can be manipulated by the kicker to achieve a desired distance.

4. How can the height of a football kick be maximized?

To maximize the height of a football kick, the ball should be kicked at a 45-degree angle. This angle allows for the greatest distance to be covered while still achieving a high enough trajectory to clear any obstacles.

5. Is projectile motion the same as uniform circular motion?

No, projectile motion and uniform circular motion are different types of motion. Projectile motion is the curved path of an object affected by gravity, while uniform circular motion is the constant motion of an object in a circular path at a constant speed.

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