Projectile Motion of a Football Problem

1. Dec 4, 2014

Esau Garcia

1. The problem statement, all variables and given/known data
A football is kicked from the ground toward a 3.2 meter tall goal post 30 meters away. The ball leaves the ground with a velocity of 18 meters/sec at an angle of 50 degrees from the ground. How high off of the ground is the ball when it reaches the goal post? Does the kicker make the field goal? How high above or below the bar is the ball when it arrives at the goal post?

2. Relevant equations

3. The attempt at a solution
This is my first thread because I'm new so bare with me. I started the problem by drawing a diagram with a vector of 18 meters/sec, the horizontal component and the vertical component. I solved for each component by using basic trig functions. The results are Vy=13.79 meters/sec and Vx=11 meters/sec. From there I used the total displacement of 30 meters divided by the vertical component of 11 meters/sec to get a time of 2.59 seconds. This time would be the moment in which the ball reaches the goalpost (Is that correct?) But I'm just having difficulty answering the questions. Thanks for the help in advance.

2. Dec 5, 2014

Mickey Tee

You've got the time at which the ball will be over head the goal post. Now just think about the motion of the ball along the vertical axis and determine how high off the ground it is. You know the inital velocity, time and acceleration.

3. Dec 5, 2014

haruspex

Does "SUVAT" ring a bell?