Falling call the movement of a body in gravitational field of Earth. Its feature is that it is always made with continuous acceleration which is equal to m/s g≈9.81². It needs to be considered and when the subject is thrown horizontally.
It is required to you
- - range finder;
- - electronic stop watch;
- - calculator.
Instruction
1. If the body freely falls from some height of h, measure it by means of a range finder or any other adaptation. Calculate the speed of falling of a body of v, having found a root square of the work of acceleration of gravity on height and number 2, v= √ (2∙g∙h). If before time reference mark the body already had v0 speed, then to the turned-out result add its v= value √ (2∙g∙h) +v0.
2. Example. The body freely falls from height of 4 m at a zero initial speed. What will be its speed at achievement of the earth's surface? Calculate the speed of falling of a body by a formula, considering that v0=0. Make substitution of v= √ (2∙9.81∙4) ≈8.86 m/s.
3. Measure time of falling of a body of t by an electronic stop watch in seconds. Find its speed at the end of an interval of time which proceeded the movement having added to the initial speed of v0 of the work of time for the acceleration of gravity of v=v0+g∙t.
4. Example. The stone began falling with an initial speed of 1 m/s. Find its speed through 2 pages. Substitute values of the specified sizes in m/s formula v=1+9.81∙2=20.62.
5. Calculate the speed of falling of the body thrown horizontally. In this case its movement is result of two types of the movement in which the body at the same time takes part. This uniform motion across and uniformly accelerated - down. As a result the trajectory of a body has a parabola appearance. Body speed will be equal to the vector sum of a horizontal and vertical component of speed at any moment. As a corner between vectors of these speeds always of a straight line, for determination of speed of falling of the body thrown horizontally use Pythagorean theorem. Speed of a body will be equal to a root square of the sum of squares of horizontal and vertical components of v= time √ at present (v of mountains² + v vert²). Count a vertical component of speed by the technique stated in the previous points.
6. Example. The body is thrown horizontally from height of 6 m with a speed of 4 m/s. Determine its speed at blow about the earth. Find a vertical component of speed at blow about the earth. It will be the same as though the body freely fell from the assigned altitude of v vert = √ (2∙g∙h). Substitute value in a formula and receive v= √ (v of mountains² + 2∙g∙h) = √ (16+ 2∙9,81∙6) ≈11.56 m/s.