Soccer goal. Need help defining height of ball at a distance.

  • Thread starter Thread starter lorenzosounds
  • Start date Start date
  • Tags Tags
    Ball Height
AI Thread Summary
The discussion centers on developing a program to determine if a kicked soccer ball crosses a goal, given user-defined variables for distance, angle, and speed. The net height is set at 2.54 meters, and gravity is acknowledged as 9.81 m/s². Participants explore various kinematic equations to calculate flight time and range, while also focusing on the ball's height at a specific distance. There is a suggestion to consider all relevant kinematic equations for both horizontal and vertical motion, and clarification is sought regarding the meaning of "A-hat" in the height equation. The conversation emphasizes the importance of understanding projectile motion principles to accurately determine if the ball clears the net.
lorenzosounds
Messages
4
Reaction score
0

Homework Statement



Write a program to determine whether or not a ball kicked is a goal. Initial distance (from goal), initial angle, and initial speed are user-defined variables. The net is 2.54 m high. Gravity is 9.81m/s^2


Homework Equations



flightTime=(2)initSpeed*sin(initAngle)/gravity

range=flightTime*initSpeed * cos(initAngle)


The Attempt at a Solution



Trying to define whether or not the ball is above the net when the ball is at the initial distance. I've been thinking about it in terms of trig functions, specifically Sin. Also, maybe using the pythagorean theorem (initDistance^2 + height of ball^2 = Length of tangent line between initDistance and ball^2).

I'm also aware of the kinematic equation vi^2 * (sinθi)^2/2g, which gives the max height of a parabolic flight. However, this doesn't let me define the height at any moment.
 
Physics news on Phys.org
I found this formula defining height.

y(t) = (Vo sinm)) - (gt²)/2

What does the A-hat represent?
 
lorenzosounds said:

Homework Statement



Write a program to determine whether or not a ball kicked is a goal. Initial distance (from goal), initial angle, and initial speed are user-defined variables. The net is 2.54 m high. Gravity is 9.81m/s^2


Homework Equations



flightTime=(2)initSpeed*sin(initAngle)/gravity

range=flightTime*initSpeed * cos(initAngle)


The Attempt at a Solution



Trying to define whether or not the ball is above the net when the ball is at the initial distance. I've been thinking about it in terms of trig functions, specifically Sin. Also, maybe using the pythagorean theorem (initDistance^2 + height of ball^2 = Length of tangent line between initDistance and ball^2).

I'm also aware of the kinematic equation vi^2 * (sinθi)^2/2g, which gives the max height of a parabolic flight. However, this doesn't let me define the height at any moment.
Welcome to Physics Forums.

"Relevant equations" should probably include all kinematic equations, applied to both horizontal and vertical motion.

You can use the kinematic equation that tells you the ball's height at any given time, given the acceleration and initial velocity.

Also, what is supposed to happen to the ball if it hits the ground before reaching the goal? Does it come to a complete stop, bounce off the ground, continue rolling along the ground, or something else?
 
lorenzosounds said:
I found this formula defining height.

y(t) = (Vo sinm)) - (gt²)/2

What does the A-hat represent?
That looks similar to the following equation (2nd equation listed under "Displacement"):
http://en.wikipedia.org/wiki/Projectile_motion#Displacement

But there is no A-hat in that equation.

I'll suggest that you look at a physics textbook, in the section that discusses projectile motion, which will have all the equations and also explain what all the terms mean.
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top