Robert is playing with his ballon top of a building, but the ball accidentally fell and hit the ground after 8.7 seconds. Determine the final velocity of the ball just before it hits the ground, determine the height of the building. ??

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Answer 1 · 2018-07-12T05:37:47

Please see the explanation below

The time is #t=8.7s#

The acceleration due to gravity is #g=9.8ms^-2#

Assume that the initial velocity is #u=0ms^-1#

Then,

Apply the equation of motion

#v=u+at#

The velocity on hitting the ground is

#v=0+g t=9.8*8.7=85.26ms^-1#

To calculate the height of the building, apply the equation

#h=ut+1/2g t^2 =0+1/2*9.8*8.7^2=370.88m#