Trajectory, does it clear a certain height problem help

In summary, this conversation discusses a problem in which a place kicker must kick a football from a distance of 45.5 m and the ball must clear a crossbar that is 3.05 m high. The ball is kicked with a speed of 19.0 m/s at an angle of 48.0° to the horizontal. By calculating the distance in the y-direction using the equation Dy = Voy * t -1/2gt^2, it is determined that the ball falls short of clearing the crossbar by 9.18 m. The individual seeking help later realizes that the 3.05 m height of the crossbar should be added to the calculated distance to get the correct answer.
  • #1
iamtrojan3
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Trajectory, "does it clear a certain height" problem help!

Homework Statement


A place kicker must kick a football from a point 45.5 m from the goal, and the ball must clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a speed of 19.0 m/s at an angle of 48.0° to the horizontal. By how much does the ball clear or fall short of clearing the crossbar?

Homework Equations


Dy = distance in y = Voy *t -1/2gt^2
Dx = ~~~ x = Vox * t
Vox = initial velocity in x
Voy = ~~~~ y

The Attempt at a Solution


I tried to express Y in terms of x...
since x = Vox * t ... t = x / Vox
then
Dy = Voy(x) / Vox - 4.9 (x^2/Vox^2) assume gravity's 9.8

Plug in 45.5 m for x
Voy = 14.12 m/s
Vox = 12.71 m/s

Dy = -12.23 m

So when the ball is 45.5 m long, its 12.23m underground. which means the ball is 12.23 - 3.05 = 9.18m short of crossing the bar.

Idk... seems simple enough but apprently the answer's wrong.

Thanks a lot for your help!
 
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  • #2


With a speed of 19.0 m/s at an angle of 48.0° to the horizontal, find the range.
 
  • #3


Ahhhhhhh i figured it out... since its "underground"... you add the 3.05 meters!
thanks for the helps anyways >.<
 

FAQ: Trajectory, does it clear a certain height problem help

1. What is trajectory and why is it important?

Trajectory refers to the path followed by a moving object through space or air. It is important because it helps us understand the motion and behavior of objects and can be used to predict their future positions.

2. How is trajectory related to clearing a certain height?

In order for an object to clear a certain height, it must follow a specific trajectory that allows it to gain enough height and distance to clear the obstacle. This trajectory is influenced by factors such as initial velocity, angle of projection, and gravitational force.

3. Can we calculate the trajectory of an object?

Yes, the trajectory of an object can be calculated using mathematical equations and formulas that take into account the object's initial velocity, angle of projection, and the forces acting upon it.

4. How does air resistance affect trajectory?

Air resistance, also known as drag, can affect the trajectory of a moving object by slowing it down and altering its path. This is especially significant for objects moving at high speeds or over long distances.

5. Are there any real-life applications of trajectory calculations?

Yes, trajectory calculations are used in various fields such as ballistics, aerospace engineering, and sports. They are also used in video games and simulations to accurately depict the motion of objects.

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