Work is equal to distance times time so no work
The wind Wind turbines work on a simple principle: instead of using electricity to make wind—like a fan—wind turbines use wind to make electricity. Wind turns the propeller-like blades of a turbine around a rotor, which spins a generator, which creates electricity.
The correct answer is (A). The speed of light would increase to a speed larger than the maximum speed of light in vacuum.
The index of refraction is the ratio of speed of light in vacuum to the speed of light in a medium.
n=C/V
here, n is the index of refraction, c the speed of light in vacuum, v is speed of light in any medium.
Now if the value of index of refraction is less than one, than the value of speed of light would be greater than the speed of light in the vacuum.
Answer:
a) Both blocks displace the same amount of water.
Explanation:
Specific gravity (S.G.) is a quantity that tells how much and object is submerged on water and is given by:
with ρ the densities
Density of water is 
and density of aluminum is 
So:
A S.G. value bigger than one means the object is totally submerged so the water displaced is equal to the volume of the cube.
For the lead (density = 
) block we're going to calculate specific gravity in this case:
Again S.G gravity is bigger than 1, so the lead block is totally submerged too, that implies the volume of water displaced is the volume of the block, that is the same volume as the aluminum block, so a is the correct one.
Answer:
- <em>In both cases the tension in the rope is </em><u>equal to 500N</u>
Explanation:
It may be that in the case of the <em>tree</em>, the result is more intuitive, because you can think that there is only one force. But this is misleading.
To find the <em>tension in the rope</em>, you should draw a free body diagram. By doing so, you would find that the rope is static because there are two opposite forces. Assuming, for simplicity, that the rope is horizontal, a force of 500N is pulling to one direction (let's say to the right) and a force of 500N is pulling to the opposite direction (to the left). Else, the rope would not be static.
That analysys is the same for the<em> rope tied to the tree</em> ( the tree is pulling with 500N, such as the man, but in opposite direction) and when the rope is pulled by <em>two men</em> on opposite ends, each with<em> forces of 500N.</em>
Hence, the tension is the same and equal to 500N.
