There are several types of work. Let’s talk about mechanical work:
W = F*d
So you need to know the force and the distance.
There are several ways to calculate the power. First:
P=W/t
So you can calculate it like that if you have already calculated the work. Remember W is F*d, so:
P=F*d/t
Remember d/t is also velocity:
P=F*v
So you can also calculate the power if you know the force and the velocity, with no need to know the work or the distance.
So in both cases we have a formula that requires to know the force<span>.
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Answer:
2. B
3. A
4. C
5. B
6. A
Explanation:
2. Sound waves use vibrating molecules to move. With this being said, sound waves would travel best through dense materials, and would travel worst in empty materials, like space. Using this information, you can infer that B would be the answer because water is denser than air and water is the densest material on that list.
3. The speed of the wave is equal to the frequency times the wavelength. Since it has a wavelength of 100 meter and 20 Hertz, the speed would 2000 m/s
4. Like noted in question 2, sound waves travel best in dense materials. Rock is the densest material in that last.
5. By looking at the chart, you can see that the speed increases by 4 m/s when the temperature increases by 10. Using simple division, you could determine that the speed would go up by 2 m/s since the jump between 15 degrees and 20 degrees is 5, which is half of 10, making the speed half of 4.
6. The speed would decrease because, like stated above, sound travels best through dense materials. Since rock is denser than air, the speed would decrease as it leaves.
Answer:c
Explanation:
Given
Object moving towards the motion detector at a constant speed
Constant speed indicates that there is no acceleration .
As the object is moving in a straight line therefore its velocity is same and do not changes with time
thus the correct option is c i.e. a straight line with zero slope.
Each electron winds up with kinetic energy of
(270 keV)
plus
(whatever KE it had when it started accelerating).
Conservation of energy just means that the total energy is unchanged.
Energy is made up of potential and kinetic, so if the total is unchanged, that means the sum of them is unchanged, which is D.