In longitudinal waves, the motion of the particles in a medium is across the direction of the wave.
Answer:
The speed of the animals is 1.64m/s.
Explanation:
Let us work with variables and call the mass of the two rats 
and 
, and the length of the rod 
.
Using the law of conservation of energy, which says the potential energies of the rats must equal their kinetic energies, we know that when the rod swings to the vertical position,
,
solving for 
, we get:
Putting in the values for , , 
, and we get:
Therefore, as the rod swings through the vertical position , the speed of the rats is 1.64 m/s.
To do that, you must pass electric current through a substance
that electrons have to spend energy to pass through.
The substance will be one that gets warm and dissipates heat
when electric current flows through it.
We'll say that the substance has "resistance", which we can measure.
The amount of heat that appears when current flows through it
will be (current²)·(resistance).
A few examples of things used for that purpose:
-- resistors
-- burners on electric stoves
-- coils of resistor-wire in a toaster
-- aquarium heater
-- electric clothes iron
-- electric coffee pot
-- blow-dryer
-- electric hair-curling iron
-- skinny tungsten wire in a light-bulb .
D. A magnetic field created by the electric current causes the compass needle to move.
