Question #26ccf

1 Answer
Aug 2, 2016

Answer:

#n=1#

Explanation:

Kinematic equation for free fall under gravity is given by
#h=ut+1/2g t^2#.
#u and t# are initial velocity and time of fall to reach ground respectively.

  • Height of #9th# storeys of the building #h#, is found by inserting given values
    #h=0xx3+1/2xx10xx3^2 =45 m#
    Height of each storey#=45/9=5m#

  • Height dropped in first second is
    #h_1=0xx3+1/2xx10xx1^2 =5 m#

  • Now height dropped in first second #5m#
    #=nxx"height of each storey"#
    #=>n=1#