Answer:
Velocity, v = 0.239 m/s
Explanation:
Given that,
The distance between two consecutive nodes of a standing wave is 20.9 cm = 0.209 m
The hand generating the pulses moves up and down through a complete cycle 2.57 times every 4.47 s.
For a standing wave, the distance between two consecutive nodes is equal to half of the wavelength.

Frequency is number of cycles per unit time.

Now we can find the velocity of the wave.
Velocity = frequency × wavelength
v = 0.574 × 0.418
v = 0.239 m/s
So, the velocity of the wave is 0.239 m/s.
Regions in the milky way where density waves have caused gas clouds to crash into each other are called clumps.Clumps are molecular clouds (interstellar clouds) with higher density,where lots of dust and gs cores resides. These clouds are the beginning of stars.
Answer:
A. If two objects collide, each object exerts a force in the same direction as the other.
Explanation:
Answer:
The mechanical energy is converted to potential energy while the kinetic energy is zero
Explanation:
mechanical energy is the sum of potential energy and kinetic energy. It is the energy associated with the motion and position of an object. The total mechanical energy is the sum of these two forms of energy.
The Law of Conservation of Energy: Energy cannot be created or destroyed, but is merely changed from one form into another. This means that potential energy can become kinetic energy, or vice versa, but energy cannot “disappear”.
The mechanical energy is converted to potential energy while the kinetic energy is zero
17. a sea breeze is a breeze blowing towards the land
18. a land breeze is a breeze blowing towards the sea