When you pick a book off the floor you are transferring kinetic energy from your hands to the potential energy of the book.
E=F*d/2 = k*d * d/2 =>
d^2= 2*E/k
d= sqrt(2*E/k)=sqrt(2*1J/1000N/m)=sqrt(20m^2)/100=0.045 m = 45 mm
Answer:
31.25 year .
Explanation:
The thickness of layer must change so the destructive interference may be converted into constructive interference . This can happen if thickness is reduced by λ /4 , so that path difference changes by 2 x λ /4 = λ /2 .
This will convert destructive to constructive interference.
change in thickness required = λ /4
= 525 / 4 nm
= 131.25 nm .
year required to wear off
= 131.25 / rate of decay
= 131.25 / 4.2
= 31.25 year .
For this case we have that a paper clip is a very small object, to be taken in the hand we feel that its mass is very small, almost imperceptible.
For this reason we can discard option D and option A.
Being so small we can use the milligrams to measure its mass, it is the smallest scale.
Answer:
Option B
Acceleration = speed/ time
a = Δv/Δ t
as Δv = v₂ - v₁ / t
a = 50m /s - 0 m/s / 60m
= 50m/s / 60m
= 0.834s⁻¹
