Answer: The correct answer would be C. Salt crystals are hard and brittle because they are made up of atoms that combine by ionic bonding.
Explanation: All the other ones are chemical changes because a new substance is formed.
Answer:
The answer is A.
Explanation:
They both work together to circulate oxygen and blood throughout the body.
Answer:
Avg.velocity=(Δy/ Δt) =(net displacement/ total time for journey)
Δy = 0
Δt = t
so avg. velocity = 0/t =0
Avg. speed =(total distance traveled/ total time for journey)
total distance = up +down = Ymax+Ymax= 2 Ymax
total time = t
avg. speed = 2 Ymax/t
Explanation:
Since there is no net displacement from the original position,velocity is zero. Claudia is right!
while it covered some distance in time t so its speed is not as qouted by Hossien
Answer: A.The total number of energy levels the electron can jump to.
Explanation:
Spectral lines are bright or dark lines over continuous spectrum which occur due to emission or absorption of energy.
When an electron jumps to or from one energy level to another energy level, spectral lines are produced. The range of spectral lines depends on the number of energy levels available to which the electron can jump. This depends the amount of energy gained/lost by the electron.
Thus, the correct answer is: A.The total number of energy levels the electron can jump to.
The eclipse usually moves from west to east as the moon rotates the Earth from west to east and the Earth rotates towards the east as well.
This means that the shadow of the moon is also moving towards the east. That's why the eclipse moves towards the east (it follows the lunar shadow).
