Se lanza desde el piso una piedra con velocidad vertical de +42 m/s. El punto de referencia se encuentra en el piso. Calcular: a). Escribir la ecuación de posición y la ecuación de la velocidad. b). Calcular en que instante su velocidad es nula. c). Calcular la máxima altura que llego. (Considerar la aceleración de la gravedad: a=9.81m/s2).

a)  y = 42 t - 4,905 t² ,      v = 42 - 9.81 t,  b)   t = 4.281 s , c)   y = 89.9 m

Explanation:

This problem is an example of vertical launch

a) the expression for the position is

         y = v₀ t - ½ g t²

we substitute

          y = 42 t - 4,905 t²

the expression for speed is

        v = v₀ - gt

        v = 42 - 9.81 t

b) the speed is null when v = 0

         v₀ = gt

          t = v₀ / g

          t = 42 / 9.81

          t = 4.281 s

c) for the maximum height we can use the expression

        v² = v₀² - 2gy

    at maximum height v = 0

         y = v₀² / 2g

     let's calculate

        y = 42 2/2 9.81

        y = 89.9 m

an energy transformation flow diagram is shown

where is it ?

the order for strong to weak forces such as

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

the fundamental forces are those forces that act between to objects or element to make interactions. there are four types of fundamental forces such as strong and weak nuclear forces (due to protons and electrons), electromagnetic force (due to the motion of electrons) and gravitational force (due to orbital movement of the planet). if these forces are arranged on the basis of their maximum strength then the order is

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force