A wooden log is displaced to a distance of 20m in 10 seconds by applying 500N effort . Calculate the workdone and power...
Solution,
displacement = 20 m
time = 10 sec
force = 500 N
work done = ?
power = ?
Now ,
work done = f × s
= 500 N × 20 m
= 10000 j
Now ,

~nightmare 5474~
Answer:
The longest wavelength of light is 209 nm.
Explanation:
Given that,
Spring constant = 74 N/m
Mass of electron 
Speed of light 
We need to calculate the frequency
Using formula of frequency

Where, k= spring constant
m = mass of the particle
Put the value into the formula


We need to calculate the longest wavelength that the electron can absorb

Where, c = speed of light
f = frequency
Put the value into the formula



Hence, The longest wavelength of light is 209 nm.
We're told that the planets have EQUAL MASS.
If that's true, then the strength of the gravitational forces between
each planet and the star depends only on the distance between
them ... the farther a planet is from the star, the smaller the
gravitational forces are IF we're talking about planets with
equal masses.
Planet-X is closer to the star, and Planet-Y is farther from it.
From this we know that the gravitational forces between the
star and Planet-X are greater, and the forces between the star
and Planet-Y are smaller.
'A' says this.
'B' is totally absurd, because it talks about gravity repelling things.
'C' says exactly the opposite for the two planets.
'D' says that distance doesn't matter. We know this is absurd,
simply because we're never pulled toward Jupiter in our daily life.
Intensity, E follows inverse square law.
E α 1/r²
r is the distance.
So if the distance r is increased by 3, the intensity would be reduced by 3²
3² = 9
So the answer is nines times as low. C.