The body is thrown at an angle to the horizon with an initial speed of 25 m / s how long the flight

The body is thrown at an angle to the horizon with an initial speed of 25 m / s how long the flight lasted if at the top point of the trajectory the body was moving at a speed of 15 m / s.

Data: Vн (initial speed of throw at an angle to the horizon) = 25 m / s; Vg (speed at the top of the trajectory, horizontal speed) = 15 m / s.

Constants: by condition g (acceleration of gravity) = 10 m / s2.

1) Find the angle of the body to the horizon: Vx = Vn * cosα, whence α = arccos (Vx / Vn) = arccos (15/25) = 53.13º.

2) Let’s calculate the flight duration: t = 2 * Vn * sinα / g = 2 * 25 * sin 53.13º / 10 = 4 s.

Answer: The flight of the thrown body lasted 4 seconds.