Answer:
The final velocity is 
Explanation:
From the question we are told that
The mass of the child is 
The initial speed of the child is 
The mass of the wagon is 
The initial speed of the wagon is 
The mass of the ball is 
The initial speed off the ball is 
Generally the initial speed of the system (i.e the child , wagon , ball) is

Generally from the law of linear momentum conservation

Here
is the momentum of the system before the ball is dropped which is mathematically represented as

=> 
=> 
and
is the momentum of the system after the ball is dropped which is mathematically represented as

=> 
So

=> 
Accrording to me Mg should be that element because <span>Magnesium forms divalent cations and is capable of accepting 2 anions such as Fluorine</span>
Voltage = (current) x (resistance)
Voltage = (1.5 A) x (2 ohms)
In order to MAKE 1.5 A of current flow through the toy car, you have to PROVIDE <em>3 volts</em> from the battery.
Answer:
(D) friction from the ground changes the ball's
kinetic energy into heat
Explanation:
When a ball is roll on the ground, the electrons in the atoms on the surface of the ground push against the electrons in the atoms on the surface of your ball that is touching the ground. A rolling ball stops because the surface on which it rolls resists its motion,that is when two surfaces come in contact with each other, the surface of one tends to oppose the motion of the other. A rolling ball stops because of friction.