Physics
posted by Lindsay .
The soccer goal is 23.05 m in front of a soccer player. She kicks the ball giving it a speed of 17.97 m/s at an angle of 25.83 degrees from the horizontal. If the goalie is standing exactly in front of the net, find the speed of the ball just as it reaches the goalie.
Do I need to use delta x = Vx x t to solve for time first? Then what?

I don't know the point of this problem: should air friction be ignored or not?
I think I would ignore air friction, which in reality is silly, but anyway.
Using the intial velocity and angle, solve for the initial vertical and horizontal velocities.
Using the vertical velocity, one needs to find the time of flight.
yf=yi+vyi*t  4.9 t^2
1=0+7.83t4.9t^2
4.9t^27.83+1=0 using the quadratic formula...
t= (7.83 + sqrt (61.320)/9.8=1/45 sec
Now, where is the ball at that time?
d= 17.97cos25.83 * time=23.45 meters, within the goalie reach of .4 meters.
Now, what is the difference in energy?
Intial energy = 1/2 mv^2
final energy= 1/2 mvf^2 + mgh where h is one meter.
vf^2= vi^2  2gh
vf= sqrt (17.97^2  2*g*1)=17.42m/s
This problem is subject to a lot of differing assumptions, the main one is friction due to air. This assumes the ball is caught by moving the arms of the goalie.
Respond to this Question
Similar Questions

Physics
The soccer goal is 23.05 m in front of a soccer player. She kicks the ball giving it a speed of 17.97 m/s at an angle of 25.83 degrees from the horizontal. If the goalie is standing exactly in front of the net, find the speed of the … 
physics
A soccer player kicks the ball toward a goal that is 28.6 m in front of him. The ball leaves his foot at a speed of 18.5 m/s and an angle of 30.6° above the ground. Find the speed of the ball when the goalie catches it in front of … 
Physics
A soccer player kicks the ball toward a goal that is 29.2 m in front of him. The ball leaves his foot at a speed of 19.1 m/s and an angle of 33.4° above the ground. Find the speed of the ball when the goalie catches it in front of … 
Physics
The soccer goal is 32.26 m in front of a soccer player. She kicks the ball giving it a speed of 20.62 m/s at an angle of 28.29 degrees from the horizontal. If the goalie is standing exactly in front of the net, find the speed of the … 
physics
A soccer player kicks the ball toward a goal that is 18.0 m in front of him. The ball leaves his foot at a speed of 19.3 m/s and an angle of 27.0 ° above the ground. Find the speed of the ball when the goalie catches it in front of … 
Physics
A soccer player kicks the ball toward a goal that is 27.0 m in front of him. The ball leaves his foot at a speed of 16.7 m/s and an angle of 36.0 ° above the ground. Find the speed of the ball when the goalie catches it in front of … 
physics
A soccer player kicks the ball toward a goal that is 15.0 m in front of him. The ball leaves his foot at a speed of 17.1 m/s and an angle of 35.0 ° above the ground. Find the speed of the ball when the goalie catches it in front of … 
physics
A soccer player kicks the ball toward a goal that is 15.0 m in front of him. The ball leaves his foot at a speed of 17.1 m/s and an angle of 35.0 ° above the ground. Find the speed of the ball when the goalie catches it in front of … 
Physics
A soccer player kicks the ball toward a goal that is 23.0 m in front of him. The ball leaves his foot at a speed of 17.6 m/s and an angle of 29.0 ° above the ground. Find the speed of the ball when the goalie catches it in front of … 
physics
A soccer player kicks the ball toward a goal that is 16,8m in front of him . The ball leaves his foot at a speed of 16,0m/s and an angle 28,0degree above the ground.Find the speed of the ball when the goalie catches it in front of …