Question

7) the observation deck of the Empire State Building is 381 m above the street. Determine the

Answer 1

Answer:

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

 

y =  1/2at2 + v0t + y0

 

v = v0 + at

 

vf2 = 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

Explanation:

Answer 2

Answer:

Penny will take 8.8178 sec for free fall

Explanation:

We have given height of the deck h = 381 m

Acceleration due to gravity $g=9.8m/sec^2$

According to second equation of motion we know that $h=ut+\frac{1}{2}gt^2$

As there is free fall so initial velocity u = 0 m/sec

So $381=0\times t+\frac{1}{2}\times 9.8\times t^2$

$t=8.8178sec$

So penny will take 8.8178 sec for free fall