Answer: 3
Explanation:
Given
One cloud is traveling at rate of 
combined velocity of the two is 
Suppose the masses of the clouds be 
Conserving momentum

Explanation:
Suppose you want to shine a flashlight beam down a long, straight hallway. Just point the beam straight down the hallway -- light travels in straight lines, so it is no problem. What if the hallway has a bend in it? You could place a mirror at the bend to reflect the light beam around the corner. What if the hallway is very winding with multiple bends? You might line the walls with mirrors and angle the beam so that it bounces from side-to-side all along the hallway. This is exactly what happens in an optical fiber.
The light in a fiber-optic cable travels through the core (hallway) by constantly bouncing from the cladding (mirror-lined walls), a principle called total internal reflection. Because the cladding does not absorb any light from the core, the light wave can travel great distances.
However, some of the light signal degrades within the fiber, mostly due to impurities in the glass. The extent that the signal degrades depends on the purity of the glass and the wavelength of the transmitted light (for example, 850 nm = 60 to 75 percent/km; 1,300 nm = 50 to 60 percent/km; 1,550 nm is greater than 50 percent/km). Some premium optical fibers show much less signal degradation -- less than 10 percent/km at 1,550 nm.
1
Answer:
distance can describe the total distance moved and displacement shows how far something has moved from its starting position (in a straight line from point a to point b) the object doesn't have to move in a straight line, but that is how displacement is measured
Answer: Relative motion
Explanation: If two objects are moving either towards or away from each other with both having their velocities in a reference frame and someone is outside this reference frame seeing the motion of the two objects.
The observer ( in his own frame of reference) will measure a different velocity as opposed to the velocities of the two object in their own reference frame. p
Both the velocity measured by the observer in his own reference frame and the velocity of both object in their reference is correct.
Velocities of this nature that have varying values based on motion referenced to another body is known as relative velocity.
Motion of this nature is known as relative motion.
<em>Note that the word reference frame is simply any where the motion is occurring and the specified laws of motion is valid</em>
<em />
For this example of ours, the reference frame of the companion is the train and the telephone poles has their reference frame as the earth.
The companion will measure the velocity of the telephone poles relative to him and the velocity of the telephone pole relative to an observer outside the train will be of a different value.
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.