The answer is either
b A system in which Newton's Laws are valid
or
c A system in which there are no external forces.
Explanation:
not a, and not d
There are energy changes in a closed system.
A closed system obeys the conservation laws in its physical description.
Answer:
so in a given orbital there can be 3 electrons.
Explanation:
The Pauli exclusion principle states that all the quantum numbers of an electron cannot be equal, if the spatial part of the wave function is the same, the spin part of the wave function determines how many electrons fit in each orbital.
In the case of having two values, two electrons change. In the case of three allowed values, one electron fits for each value, so in a given orbital there can be 3 electrons.
A. the carbons are unbalanced
B. the hydrogens are unbalanced.
D. the chlorines are unbalanced.
That leaves C. to be correctly balanced.
Let say the two train cars are of masses 
and 
now if the speed of two cars are 
and 
then we can say that the momentum of two cars before they collide is given by
here two cars are moving in opposite direction so we can say that the net momentum is subtraction of two cars momentum.
Now since in these two car motion there is no external force on them while they collide
So the momentum of two cars are always conserved.
hence we can say that the final momentum of two cars will be same after collision as it is before collision
The approximate amount of thrust(force) you need to apply to the lander to
keep its velocity roughly constant is zero.
<h3>What is Newton's second law of motion?</h3>
Newton's second law of motion states that the acceleration the force acting
on the object is directly proportional to its rate of change of momentum.
F = m a
If the object is moving with uniform velocity, it simply means that the
acceleration is zero, and the corresponding force will also be zero.
Read more about Constant velocity here brainly.com/question/3052539
