This phenomena is also called the Doppler shift. When the source of light is approaching towards an observer, the color tends to be blue shifted, but when the source is moving away or being stretch, the color tends to red shifted. In astronomy it can be use how fast galaxy is moving towards us or how fast it moves away.
Acceleration = (change of speed) / (time for the change)
Change in speed = (22 - 4) = 18 m/s.
Time for the change = 3 sec.
Acceleration = 18/3 = 6 m/s per second.
Answer:

Explanation:
When the rock is immersed in unknown liquid the forces that act on it are shown as under
1) Tension T by the string
2) Weight W of the rock
3) Force of buoyancy due to displaced liquid B
For equilibrium we have 
=
When the rock is suspended in air for equilibrium we have

When the rock is suspended in water for equilibrium we have
+
=
Using the given values of tension and solving α,β,γ simultaneously for
we get

Solving for density of liquid we get


Answer:
Formally stated, Newton's third law is: For every action, there is an equal and opposite reaction. The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object.
Explanation:
this is what i know but i am sorry if this doesn't help
Answer:
Rubber or plastic covers are bad conductors of electricity. So they do not allow the electric current to pass through it.
Explanation:
Rubber and plastic are bad conductors of electricity, therefore when handling a tool with a rubber handle, the electricity will not pass through it.