A. 0.5kg
To get this answer you need to follow the equation of KE=0.5*mv^2
But we don't have the m part in the equation. So just plug in the numbers to see which works best, though I can tell you before we do that the answer would be a.
As you may know, gravity, is a force of 9.8 m/s. And we want to get 9.8 Joules. So if we take a half a kg stone, release it at one meter, we get half of the normal gravity pull, 4.90 Joules. That means if we take half a kg stone and drop it at a doubled height, we get 9.8 Joules.
That is also to say that if we have a 1kg stone and drop it at one meter you will get the normal pull of gravity in Joules, 9.8J.
Be careful though, this does not mean if you drop a 1kg stone and a .5 kg stone the 1kg will hit first. This simply means that the 1kg stone will have twice the Joules that the .5kg stone has.
False, the spinning coil of wire that moves the cone in a speaker does not produces sound.
<u>Explanation</u>:
The wire coil is an electromagnet that is fixed to speaker cone. A normal magnet attached to the back of the speaker cone.When audio is sent in the form of short bursts of electric current to the speaker cone through the wire.
A magnetic field is induced when electric current allowed to pass through the coil. This magnetic field is repelled by the other magnet. This repulsion cause the cone to move forward. In the absence of electric current in the coil, the cone moves backward.
Thus sound waves are produced due to the resulting rarefaction and compression. So it is not the spinning coil of wire but he permanent magnet that produces the sound.
Explanation:
The water cycle basically involves five steps:
- evaporation and transpiration ⇄
- condensation, ⇄
- precipitation, ⇄
- runoff, ⇄
- infiltration ⇄
So when a <u>thunderstorm </u>occurs it <em>helps in completing the precipitation process </em>by enabling the release of water vapor stored up in the atmosphere to fall on the ground as rain.
After this, the water <em>runoffs </em><em>to the surface of the ground, on plants, into rocks, rivers, and lakes.</em>
Next, the <em>Infiltration process</em> enables the water on the ground surface to enter the soil some of which becomes groundwater.
The cycle begins again as the<em> </em><em>evaporation and transpiration</em> <em>process </em>begins, where the groundwater as a result of heat from the sun is taken back into the atmosphere, while water in plants by means of transpiration goes back <em>into the atmosphere</em>.
It then <em>condenses </em>and falls back as precipitation again.