A: is potential
C: is losing kinetic energy and gaining potential energy
B: kinetic energy is at its highest
D: is loosing potential energy and gaining kinetic energy
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
The ancient Greeks, in a theory that was suggested around 450 BC, believed that everything was from from four elements. These elements included earth, water, air and fire. Later, Aristotle supported this theory.
Therefore, the first option is correct.
Answer:
D. Airplane wings must be designed to ensure that air molecules move more rapidly over the top surface of the wing, creating a region of lower pressure.
Explanation:
Bernoulli's theory operates on the assumption that its shape makes the air travel more over the top of the wing than under it as a plane moves through the air. Due to the pressure difference, wings feel a lifting force and create lift force. when pressure decrease than the velocity of the fluid will increase.
Therefore the answer is D.
