posted by Laura on .
A home run is hit such a way that the baseball just clears a wall 19 m high located 149 m from home plate. The ball is hit at an angle of 40◦ to the horizontal, and air resistance is negligible. Assume the ball is hit at a height of 2 m above the ground.The acceleration of gravity is 9.8 m/s2 . What is the initial speed of the ball? Answer in units of m/s.
Write and solve simultaneously two equations in two unknowns:
(1) the time of flight to the wall, T, and (2) the initial speed of the ball, V. The two equations describe the horizontal and vertical positions when the ball reaches the wall.
Y = 2 + Vsin40*T -(4.9)T^2 = 19
X = Vcos40*T = 149
There will be two solutions. Choose the one with positive T