Formula for distance is d=st
so for speed is s=d/t
48 km per hour
Explanation:
(9) Acceleration due to gravity is defined as the acceleration between two massive bodies when they are moving under free fall.
The relation between g and G is given by :

Where
G is universal gravitational constant
M is mass of the earth
r is distance
(10) The unwanted product that can toxify the crops are called weeds. To control weeds, a chemical called weedicides are sprayed in the field. Some other methods to control them are Ploughing or tilling of soil etc.
Here since both children and merry go round is our system and there is no torque acting on this system
So we will use angular momentum conservation in this

now here we have



Now when children come to the position of half radius
then we will have



now from above equation we have

