The shape of a liquid can change because the atoms in it are not close together to form a solid, they flow freely.
Answer: 7.5 rev/s
Explanation:
We are given the angular velocity
a helicopter's main rotor blades:

However, we are asked to express this
in the International Systrm (SI) units. In this sense, the SI unit for time is second (
):


D. Speed and direction, this is because velocity is a vector quantity so has a magnitude and direction assigned to it because it is the rate of change of displacement.
<span>When two waves of same frequency travel in a medium simultaneously in the same direction then, due to their superposition, the resultant intensity at any point of the medium is different from the sum of intensities of the two waves. At certain points the intensity of the resultant wave has a large value while at some points it has a very small or zero. This is called wave interference.</span>