High School Physics help? (A home run in a baseball game is hit in such a way that the ball just clears...)?

You have to start by using the equation of motion: y = x tan(theta) - x^2 g /2(Vint)^2(cos(theta)^2 That's Y equals X times the tan(theta) MINUS X squared times g divided by (2 times the initial velocity squared times cos(theta) squared) This equation will give you the value of y for any value of x. However, this equation is valid only when you begin at the origin, x=0 and y=0. The problem has the ball beginning at X = 0 and Y=1.1m and ends at X=131m and Y =1.97m.

Just raise the coordinate axes so that the origin makes X and Y both equal to zero, then the fence is at X=131m, and the new Y = .87m. Now you can use the trajectory equation above with: X=131m Y=.87 (in effect, this is the height that the balls has to clear, since we cut off the bottom 1.1m of the fence by raising the axes) theta = 49 degrees g = 9.81 m/s^2 Plug those numbers in the big equation, and then you can solve for the initial velocity. I got Vint = 36.12859 m/s.

This is the answer to part B. Now you can calculate anything about the path of the ball. For the time, use X = (Vint)(cos(theta)) t.

Where X=131, theta = 49 degrees, Vint = 36.12859 m/s I got t = 5.526846 s To find the velocity when the ball clears the fence, use V = sqrt Vx^2 + Vy^2 that is, the magnitude of the velocity (the speed) is the square root of the X component squared plus the Y component squared. Find Vx using X = (Vint) cos(theta) (t) I got Vx =23.70248 m/s find Vy using Y = (Vint) sin(theta) - gt Remember Y=.87 m, since we moved the axes up so that the problem begins at the origin (0,0) and then the big equation is valid. I got Vy = - 26.951766.

Notice the minus sign. That makes sense because the Y component of the Velocity is pointing downward. Just square Vx and Vy, add the squares together and take the square root.

I got V = 35.891581 m/s. This is a little less than Vint, as it should be. After the ball goes over the fence, it will hit the ground with the same Velocity that it began with, 36.12859 m/s.

Hope this helps.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.