Waves carry energy from one place to another. Because waves carry energy, some waves are used for communication, eg radio and television waves and mobile telephone signals. ... Some types of waves need to be transmitted through matter, either a solid, liquid or a gas. For example, water waves have to travel in water.
<span>Velocity, you divide distance/time </span>
The least number of component of a vector quantity is two. These are the x-component and the y-component.
The resultant vector, or vector as we refer to it in this item, can be calculated through the equation,
RV = sqrt ((Vx)² + (Vy)²)
From the equation, it can be noted that if we let Vx equal to zero,
RV = Vy
Similarly, if we let Vy be equal to zero then,
RV = Vx
Thus, it is still possible for the vector to become nonzero even if one of its components is zero.
Answer:
1000 kgm²/s, 400 J
1000 kgm²/s, 1000 J
600 J
Explanation:
m = Mass of astronauts = 100 kg
d = Diameter
r = Radius = 
v = Velocity of astronauts = 2 m/s
Angular momentum of the system is given by

The angular momentum of the system is 1000 kgm²/s
Rotational energy is given by

The rotational energy of the system is 400 J
There no external toque present so the initial and final angular momentum will be equal to the initial angular momentum 1000 kgm²/s

Energy

The new energy will be 1000 J
Work done will be the change in the kinetic energy

The work done is 600 J
Hubble noticed that the galaxies were moving away from us, which meant the universe was expanding.
This is why constellations change over time. In some years, the Big Dipper won't actually look like a dipper anymore.