The speed of electromagnetic waves in a vacuum is the same as the speed of light. It can be measured by finding the frequency and wavelength of two different waves, and then by that correlation, the speed of the waveform.
Hope this helps you (:
Answer:
Multiple choice answer would be "None"
Explanation:
White dwarfs are radiating stored heat from earlier reactions.
Technically, it would be the last fusion stage the star went through
BEFORE it became a white dwarf, but that's nit-picking.
<u>#2</u>
Use the formula ... Kinetic energy = (1/2) x (mass) x (speed)²
<u>#3 - a).</u>
sun => energy travels as electromagnetic waves => reaches Earth as
heat & light energy.
sun => absorbed in plants => eaten by animals => animals die =>
decay into oil in millions of years => we burn the oil to get the energy.
<u>#3 - b).</u>
food I ate for lunch => metabolized into glucose by my body
=> some of it burned in my muscles to generate energy for immediate needs
=> the rest of it stored as fat for future needs.
<u>#3 - c).</u>
flower pot rolls off the ledge => gravity does work on it all the way down,
producing the kinetic energy it has when it hits the floor.
<u>#3 - d).</u>
oil or natural gas is burned, releasing heat energy => energy is used
to generate electricity => electricity flows through cables from the
power generating plant to your home => hot plate plugged into the
wall => turns electrical energy back into heat energy => heat energy
is conducted into the bottom of the beaker, flows through the glass
to the inside surface => heat energy is conducted from the inside of
the glass to the water, which gets hotter as it absorbs more energy.
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<u>Note:</u>
#1 on the sheet is wrong.
"Work = force x distance" that's correct
But 25-kg is the <em>mass</em> of the ball, <em>not </em>the gravitational <em>force </em>on it.
The force on it is (mass) x (gravity), called its "weight".
That's (25-kg) x (9.8 m/s²) = 245 kg-m/s² = 245 newtons .
Answer:
The spring's maximum compression will be 2.0 cm
Explanation:
There are two energies in this problem, kinetic energy 
and elastic potential energy 
(with m the mass, v the velocity, x the compression and k the spring constant. ) so the total mechanical energy at every moment is the sum of the two energies:
Here we have a situation where the total mechanical energy of the system is conserved because there are no dissipative forces (there's no friction), so:
Note that at the initial moment where the hockey puck has not compressed the spring all the energy of the system is kinetic energy, but for a momentary stop all the energy of the system is potential elastic energy, so we have:
(1)
Due conservation of energy the equality (1) has to be maintained, so if we let k and m constant x has to increase the same as v to maintain the equality. Therefore, if we increase velocity to 2v we have to increase compression to 2x to conserve the equality. This is 2(1.0) = 2.0 cm
