<span>
At the Earth's surface, warm air expands and rises, creating
what is known as an area of low pressure.
Cold air is dense and sinks to the surface to create what is
known as an area of high pressure.</span>
On question 30, that is a displacement- time graph (DT). On this type of graph the gradient is equal to the velocity. B has the steepest gradient, then A and finally C
Now velocity is a vector quantity so it has a direction and speed ( speed doesn't have a fixed direction.)
on the DT graph im going to assume that movement B is a positive velocity with A and C being negative.
So by ranking these: A is the most negative, C is the least negative and B has to be the greatest as it is the only positive velocity.
Q31, The same type of graph is present, by looking at the gradients we can rank the largest and smallest velocities- speeds in the case of the question.
i'll skip my working out as its the same as before:
C, B, A and then D
the same idea as on Q30 applies to Q31 part b,
D,C,B then A
Answer:
states that the rate of diffusion of gases is inversely proportional to their square roots
Crushing pressure. Human bodies are used to air pressure. The air pressure in our lungs, ears and stomachs is the same as the air pressure outside of our bodies, which ensures that we don't get crushed. Our bodies are also flexible enough to cope when the internal and external pressures aren't exactly the same.
