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A construction worker drops a brick off a high scaffold. If the brick lands 5.0 s later, how fast was the brick travelling the instant before hitting the ground?

Respuesta :

Answer:

The brick was traveling at 49 m/s the instant before hitting the ground.

Explanation:

When an object is dropped from rest in a free-falling motion, it falls with a constant acceleration called the acceleration of gravity, which value is [tex]g = 9.8 m/s^2[/tex].

The final velocity of a free-falling object after a time t is given by:

[tex]vf=g.t[/tex]

The distance traveled by a dropped object is:

[tex]\displaystyle y=\frac{gt^2}{2}[/tex]

The brick takes 5 seconds to land from the high scaffold. The speed at which it lands is:

[tex]vf=9.8\cdot 5[/tex]

vf=49 m/s

The brick was traveling at 49 m/s the instant before hitting the ground.