According to Doppler Effect, an observer at rest will perceive a shift in the wavelength or frequency of the radiation emitted by a source in movement.This shift is given by the formula:
where:
= observed wavelength
= wavelength at rest
v = speed of source (positive if towards the observer, negative if away from the observer)
c = speed of light
Therefore, we can solve for the observed wavelength:
Substituting the given data:
= 655.80 nm
Hence, the observed wavelength of the line would be
655.80 nm. Note that this value is smaller than the one at rest, which means that we have a blue-shift, as expected for an approaching source.
Answer:
Vertical velocity decreases.
Explanation:
The motion of the ball is a projectile ball, which consists of two independent motions:
- a horizontal motion, with constant velocity
- a vertical motion, with constant acceleration g=9.8 m/s^2 towards the ground
In the vertical motion, there is a constant acceleration directed downward: this means that the vertical velocity decreases as the ball goes higher. In fact, it decreases following the equation
And it decreases until the ball reaches its maximum height, then it starts increasing again.
Answer:
G. it enables people to use pots and pans made of metal to cook food
Explanation:
Metals are known to be substances with a relative high melting point, which means that it takes a very high temperature to melt them. As used in this question, copper (Cu) and iron (Fe) at metallic elements that have high melting points.
One advantage of this property based on the options provided is that "it enables people to use pots and pans made of metal to cook food". This is because cooking food requires subjecting them to a constant temperature from a heat source e.g cooker or stove.
The material used to hold the food being cooked must possess a very high melting point to withstand the heat, hence, the importance of these metallic substances. Most pots and pans are made of steel, an alloy of iron, hence, they have high melting point.