Question

Una bola de acero rueda y cae por el borde de una mesa desde 4ft por encima del piso. Si golpea el suelo a 5ft de la base de la mesa, ¿cual fue su velocidad horizontal inicial?

Answer 1

Answer:

     $\large\boxed{\large\boxed{10ft/s}}$

Explanation:

The question, translated, is:

• A steel ball rolls and falls off the edge of a table from 4ft above the floor. If you hit the ground 5ft from the base of the table, what was your initial horizontal velocity?

Solution

This is a projectile motion, for which, the equations that you will need are:

    $V_x_0= V_x=x\cdot t$

     $y=y_0+Vy_o\cdot t-g\cdot t^2/2$

1. Calculate the time that it takes the ball to fall 4ft

    $0=4ft-g\cdot t^2/2\\\\t^2=2\times 4ft/( 32.174ft/s^2)=0.24865s^2\\\\t=0.4986s$

2. Calculate the horizontal velocity:

     $V_x_0= V_x=x\cdot t\\\\V_x_0=5ft/0.4986s=10.027ft/s\approx 10ft/s$