Answer:
So coefficient of kinetic friction will be equal to 0.4081
Explanation:
We have given mass of the block m = 0.5 kg
The spring is compressed by length x = 0.2 m
Spring constant of the sprig k = 100 N/m
Blocks moves a horizontal distance of s = 1 m
Work done in stretching the spring is equal to 
This energy will be equal to kinetic energy of the block
And this kinetic energy must be equal to work done by the frictional force
So 


So coefficient of kinetic friction will be equal to 0.4081
Answer:

Explanation:
By Einstein's Equation of photoelectric effect we know that

here we know that
= energy of the photons incident on the metal
= minimum energy required to remove photons from metal
= kinetic energy of the electrons ejected out of the plate
now we know that it requires 351 nm wavelength of photons to just eject out the electrons
so we can say

here we know that

now we have

now by energy equation above when photon of 303 nm incident on the surface





Answer:
shown below
Explanation:
2 x 10⁷ as a number is 20,000,000
20,000,000 - 10 = 19,999,990
It went 19,999,990 m/h
in km/h:
19,999,990 / 1000 = 19,999.99 km/h
in km/s
19,999,990 / 3,600,000 = ~5.56 km/s
in m/s
19,999,990 / 3600 = ~5555.56 m/s
It is actually HR signifies a house bill and s signifies a senate bill