Mathematics problem, please help me out .. I rate 100%

in the bottom of the 9th inning, the bases are loaded and the braves are down by three runs. chipper johns steps to the plate. twice he swings and misses. The crowd heads for the exits. the next pitch is a fast ball down the middle. he swings and makes perfect contact with the ball, sending it up at 45 degree towards the fence 400 ft away.

a.determine how fast he must hit the ball to land at the base of the fence, neglecting the air resistance.

b. Determine whether there was a better angle at which to hit the ball so that it could clear a 12 ft fence.


please help me out, Thanking you in advance. I rate for sure.

You didn't give a height from which the ball was hit. We'll assume it's from a height of 4 ft.

x(i) = 0 x(f) = 400
y(i) = 4 y(f) = 0 (Note: y(i) is my assumption since you didn't give an initial height).

v(f) = 0
v(i)(x) = v(i) * cos(45)
v(i)(y) = v(i) * sin(45)

v(f)^2 = v(i)^2 + 2 * a * (y(f) - y(i))
0 = [v(i)*sin(45)]^2 + 2 * 32.15 * (0 - 4)
******0 = v(i)^2*sin^2(45) - 257.2******

v(f)^2 = v(i)^2 + 2 * a * (x(f) - x(i))
0 = [v(i)*cos(45)]^2 + 2 * 0 * (400 - 0)
******0 = v(i)^2*cos^2(45)******

Set these 2 equations equal to each other:

v(i)^2*sin^2(45) - 257.2 = v(i)^2*cos^2(45)
v(i)^2(sin^2(45) - cos^2(45)) = 257.2
v(i)^2 = 257.2
v(i) = 16.037 ft/sec

As for part B, the best angle to hit something is at 45 degrees, so there is no better angle.