The ball is thrown vertically downward at a speed of 10 m / s. how long will its speed become equal to 40 m / s?

Initial data: V0 (the speed with which the ball was thrown down) = 10 m / s; V (the speed that the ball will reach when falling) = 40 m / s.

Constants: g (acceleration of gravity, acceleration of the body, a) = 10 m / s ^ 2.

The time when the ball reaches a speed of 40 m / s can be expressed from the formula:

V = V0 + a * t, whence t = (V – V0) / a.

Let’s do the calculation:

t = (40 – 10) / 10 = 30/10 = 3 s.

Answer: The ball speed will be 40 m / s after 3 seconds.