# What is meant by free fall? A ball is dropped from the roof of a building. It take 10 seconds to reach the ground. Find the height of the building. (g=9.8m/s2) .

2
by srujAbhidevithapa

2016-02-28T11:49:24+05:30
The fall of a body from a height towards earth under gravitational force with no other force acting on it is called free fall.
sol. t = 10s
g = 9.8 m s^-2
S = ut+1/2at2
s=0+1/2*9.8*10*10
s=490m
but in free fall it's the speed of the object...
no 9.8 is g
speed and acceleration is totally different
oh, no-no you are right...i am wrong...sorry
edit it fast
2016-02-28T11:49:29+05:30

When an object falls from any height under the influence of gravitational force only, it is known as free fall. In the case of free fall no change of direction takes place but the magnitude of velocity changes because of acceleration.

This acceleration acts because of the force of gravitation and is denoted by ‘g’. This is called acceleration due to gravity

S = ut+1/2at2

s=0+1/2*9.8*10*10
s=490m