Question:
Diffusion is the movement of particles from high to low concentration. True or False
Answer:
True.
Explanation:
Diffusion is a process that allows the movement of substance or particles in and out of cells through a semipermeable membrane.
Diffusion is a process that allows the spread or movement of particles from the region of higher concentration to a region of lower concentration through a semipermeable membrane.
Diffusion only occurs in gases and solution but not in solids, it also occurs only where particles can move freely.
Note: When particles move from the region of higher concentration to a lower concentration, it gives room for even, uniform and random distribution of particles.
Answer:

Explanation:
Mass of block=10 kg
Applied horizontal force =F=20 N
Friction force=f=10 N
We have to find the acceleration of block.
Net force=Applied horizontal force-friction force

Where F= Horizontal force
f=Friction force
m=Mass of object
a=Acceleration of object


Hence, the acceleration of the block=
An air mass is a large pocket of air with a uniform temperature and humidity
Answer:
The found acceleration in terms of h and t is:

Explanation:
(The complete question is given in the attached picture. We need to find the acceleration in terms of h and t in this question)
We are given 3 stages of movement of elevator. We'll first model them each of the stage one by one to find the height covered in each stage. After that we'll find the total height covered by adding heights covered in each stage, and equate it to Total height h. From that we can find the formula for acceleration.
<h3>
</h3><h3>
Stage 1</h3>
Constant acceleration, starts from rest.
Distance = 
Velocity = 
<h3>Stage 2</h3>
Constant velocity where
Velocity = 
Distance =
<h3>

</h3><h3 /><h3>Stage 3</h3>
Constant deceleration where
Velocity = 
Distance =

<h3>Total Height</h3>
Total height = y₁ + y₂ + y₃
Total height = 
<h3 /><h3>Acceleration</h3>
Find acceleration by rearranging the found equation of total height.
Total Height = h
h = 5a(t₁)²
