the observation deck of a tall skyscraper is 370m above the ground. calculate the time required for the penny to free fall this distance.

Question

the observation deck of a tall skyscraper is 370m above the ground. calculate the time required for the penny to free fall this distance.

Answer 1

Questions involving accelerating objects, including those in free fall, can be solved using three equations

 

y =  1/2at² + v₀t + y₀

 

v = v₀ + at

 

v_f² = v₀² + 2 a (y - y₀)

 

In this case, only the first equation is needed.

 

Since the object is falling the final height is 0 meters, the initial height is 370 m, and the acceleration is -9.8ms^_-2

 

Since the object is dropped, the initial velocity is 0.

 

0 = 1/2(-9.8)t² + 370.    t = sqrt(370/4.9) = 8.69 s