Answer: The correct statements are:
- The atoms are very attracted to one another.
- The atoms are held tightly together.
Explanation:
Solid state: In this state, the molecules are closely packed and cannot move freely from one place to another that means no space between them and the intermolecular force of attraction between the molecules are strong.
In solid substance, the particles are very close to each other due to this the intermolecular forces of attraction are strongest.
The key point about solid are:
- The atoms are very attracted to one another.
- The atoms are not moving freely.
- It will not spread out evenly to fill any container.
- The atoms are held tightly together.
- The forces of attraction are strong to bring molecules together.
- The atoms are close and in fixed positions.
B
the second chart shows a constant acceleration
Answer:
B. nuclear fusion
Explanation:
Atomic fusion is a process in which two or more lighter nuclei combine to form a heavier nucleus.
The mass of the single nucleus thus formed is lighter than the initial mass.
There is a difference in mass in the heavier nucleus thus formed. According to Einstein's mass-energy equation, the change in mass is equated towards energy.
The energy liberated in the process is called as thermo-nuclear energy.
As in the case of isotopes of hydrogen fuses to form helium, the nuclear reaction is given by relation
₁H³ + ₁H² → ₂He⁴ + ₀n¹ + energy
Thus, the nuclear reaction of hydrogen isotopes forming helium is nuclear fusion.
Acceleration is given by:
where
v is the final velocity
u is the initial velocity
t is the time interval
Let's apply the formula to the different parts of the problem:
A) 
Let's convert the quantities into SI units first:
t = 4.0 min = 240 s
So the acceleration is
B) 
As before, let's convert the quantities into SI units first:
t = 94 s
So the acceleration is
C) 
For this part we have to use a different formula:
where we have
v = 0 is the final velocity
u = 89.2 m/s is the initial velocity
a is the acceleration
d = 75 m is the distance covered
Solving for a, we find
Explanation:
The given statement is absolutely true. this is because magnitude of a vector is always non negative, it can not be zero unless its a zero vector. So, in the given question, final position vector of a moving object has a smaller magnitude than the initial position vector, so, magnitude is neither zero nor negative. Hence, it has a positive magnitude.
