Juan y Pedro transportan una caja que pesa 120,00 Lb sobre una tabla uniforme de 12 pies de largo y peso de 44,5 Lb. El peso de 120 Lb está a 4,9 pies de Pedro. ¿Cuál es el módulo de la fuerza en Lb que debe ejercer Pedro por el extremo derecho de la tabla horizontal para sostener este peso?

   F = 93.25 lb

Explanation:

To solve this problem let's use the rotational equilibrium condition

         Σ τ = 0

let's fix a reference system located at the end of the table, the position of Juan and assume the counterclockwise turns as positive

        F_jhon 0 - w l / 2 - W (l-4.9) + F l = 0

        F = w l / 2 + W (l -4.9) / l

where w is the weight of the table and W the weight of the box

let's calculate

        F = (44.5 12/2 + 120 (12- 4.9)) / 12

        F = 93.25 lb

explanation:

earth's surface is mainly heated by the absorption of infrared radiation from the sun.

evaporation occurs because molecules in liquid water are warmed ( usually by the sun) and vibrate quicker, becoming less dense and rise.

condensation occurs because molecules in water vapor are cooled and therefore vibrate more slowly thus becoming more dense and eventually fall to earth.

lines of equal barometric pressure on a weather map are called: isobars : lines of equal temp on a weather map are called: isotherms.​

increases it