Answer:
the second time there is a gas between you and the star,
Explanation:
When you observe the star for the first time you do not have a given between you and the star, therefore you observe the emission spectrum of the same that is formed by lines of different intensity and position that indicate the type and percentage of the atoms that make up the star.
When you observe the same phenomenon for the second time there is a gas between you and the star, this gas absorbs the wavelengths of the star that has the same energies and the atomisms and molecular gas, therefore these lines are not observed by seeing a series of dark bands,
The information obtained from the two spectra is the same, the type of atoms that make up the star
Answer:
Explanation:
As per work energy theorem we know that work done by all the forces must be equal to change in kinetic energy of the car
So here when brakes are applied then work is done by the brakes which is equal to change in kinetic energy of the car
so we know that work done by the brakes is given as
now we will have
1) The kinetic energy of an object is given by:
where m is the object's mass and v its speed.
By using this equation, we find the initial kinetic energy of the skateboarder:
and the final kinetic energy as well:
So, her change in kinetic energy is
2) The work-energy theorem states that the work done to increase the speed of an object is equal to the variation of kinetic energy of the object:
Therefore, the work done by the skateboarder is
Answer:
The correct answer is D)
Explanation:
When an electric magnet is brought near a cord with an electric current, the cord will most likely deflect away from the magnet because electric fields flowing through a wire generates its own magnetic field.
Cheers!
Explanation:
When a charged particle describes a circular path in a uniform magnetic field, the charged particle experiences a magnetic force towards the center of circular path, according to Fleming's left hand rule. Therefore the magnetic force and velocity (tangent to circular path) are perpendicular to each other during the circular motion. As the direction of displacement, is the direction of velocity, hence force and displacement are perpendicular to each other.
Therefore work done by magnetic force,
W=Fscos90=0
