Answer:

Explanation:
A closed system is a system where exists energy interactions with surroundings, but not mass interactions. If we neglect any energy interactions from boundary work, heat, electricity, magnetism and nuclear phenomena and assume that process occurs at steady state and all effects from non-conservative forces can be neglected, then the equation of energy conservation is reduce to this form:
(1)
Where:
- Change in kinetic energy of the system, measured in joules.
- Change in gravitational potential energy of the system, measured in joules.
If we know that
and
, then we get the following equation:
(2)
Where
and
stands for initial and final states of each energy component.
Hence, the right answer is 
Answer:
0.900 mol/kg
Explanation:
Molality is moles of solute per kilograms of solvent.
Converting 54 grams of NaOH to moles:
54 g NaOH × (1 mol NaOH / 40.00 g NaOH) = 1.35 mol NaOH
So the molality is:
m = (1.35 mol) / (1.50 kg)
m = 0.900 mol/kg
The question is missing, however, I guess the problem is asking for the value of the force acting between the two balls.
The Coulomb force between the two balls is:

where

is the Coulomb's constant,

is the intensity of the two charges, and

is the distance between them.
Substituting these numbers into the equation, we get

The force is repulsive, because the charges have same sign and so they repel each other.
Answer:
1: D- attach the muscle to bones and allow for movement
2:A- skeletal
3. A- speaking
Explanation: