you need
  • - rangefinder;
  • - electronic stopwatch;
  • - Calculator.
If a body falls freely from some height h, measure it using a range finder, or any other device.Calculate the speed falling bodies v, find the square root of the product of the acceleration of free fall to the height and the number 2, v = √ (2 ∙ g ∙ h).If before the countdown body already had speed v0, then to get the results, add its value v = √ (2 ∙ g ∙ h) + v0.
example.The body falls freely from a height of 4 m with zero initial velocity.What will it speed when reaching the earth's surface?Calculate the speed body falling under the formula, given that v0 = 0.Make the substitution v = √ (2 ∙ 9,81 ∙ 4) ≈8,86 m / s.
Measure fall time body t electrons stopwatch in seconds.Find it speed at the end of the length of time that lasted the movement adding to the initial velocity v0 product time to the acceleration of the fall v = v0 + g ∙ t.
example.Stone began to fall from an initial speed of w 1 m / s.Find it speed of 2 seconds.Substitute the values ​​of these variables in the formula v = 1 + 9,81 ∙ 2 = 20.62 m / s.
Calculate speed fall body thrown horizontally.In this case its movement is the result of two types of motion, which simultaneously participates body.This uniform motion and the uniformly accelerated horizontal - vertical.As a result, the trajectory of the body has the form of a parabola.The speed of the body at any time will be equal to the vector sum of the horizontal and vertical velocity component.Since the angle between these speeds are always straight, to determine the velocity of the fall body thrown horizontally, use the Pythagorean theorem.The speed of the body is equal to the square root of the sum of the squares of the horizontal and vertical components of a given time v = √ (v + v vert² gor²).The vertical component of the velocity is calculated according to the method described in the preceding paragraphs.
example.The body thrown horizontally from a height of 6 m from speed w 4 m / s.Define it speed when hitting the ground.Find the vertical component of the velocity on impact.It will be the same as if the body falls freely from a predetermined height vert v = √ (2 ∙ g ∙ h).Substitute a value in the formula and get v = √ (v gor² +2 ∙ g ∙ h) = √ (16+ 2 ∙ 9,81 ∙ 6) ≈11,56 m / s.