The change in potential energy of an object is given by

where
m is the mass of the object
g is the gravitational acceleration

is the increase in altitude of the object
In our problem,

is the mass of the book,

and

is the increase in altitude of the book, so its variation of potential energy is
<span>If the mass of one object halves,the new force of attraction is also get halved, as they are directly proportional to each other.
Hope this helps!</span>
Badminton is played to a score of 21 points
Answer:
D
Explanation:
the total speed and the total mass of the entire system remain the same weather one object is moving or stationary.
When two or more objects collide, the collision does not change the
total momentum of the two objects.
Whatever momentum is lost by one object in the collision is gained
by the other. The total momentum of the system is conserved.