they're called stellar black holes and only very large stars can form them because they have enough mass to do so
When a wave enters a new medium at an angle, it bends, or refracts. is the bending of a wave as it enters a new medium at an angle other than 90 degrees. Refraction occurs because waves travel at different speeds in different mediums. ... You have probably noticed the refraction of light waves in water.
Hope this helped
<h3 />
The question is incomplete. The complete question is :
A viscoelastic polymer that can be assumed to obey the Boltzmann superposition principle is subjected to the following deformation cycle. At a time, t = 0, a tensile stress of 20 MPa is applied instantaneously and maintained for 100 s. The stress is then removed at a rate of 0.2 MPa s−1 until the polymer is unloaded. If the creep compliance of the material is given by:
J(t) = Jo (1 - exp (-t/to))
Where,
Jo= 3m^2/ GPA
to= 200s
Determine
a) the strain after 100's (before stress is reversed)
b) the residual strain when stress falls to zero.
Answer:
a)-60GPA
b) 0
Explanation:
Given t= 0,
σ = 20Mpa
Change in σ= 0.2Mpas^-1
For creep compliance material,
J(t) = Jo (1 - exp (-t/to))
J(t) = 3 (1 - exp (-0/100))= 3m^2/Gpa
a) t= 100s
E(t)= ΔσJ (t - Jo)
= 0.2 × 3 ( 100 - 200 )
= 0.6 (-100)
= - 60 GPA
Residual strain, σ= 0
E(t)= Jσ (Jo) ∫t (t - Jo) dt
3 × 0 × 200 ∫t (t - Jo) dt
E(t) = 0
Answer: The correct option is B.
Chromosomes contain genes that tell the body how to grow and work.
Explanation:
This is because chromosomes contain alot of human genes which are found in the nucleus and every humans have 23 pairs of chromosomes. The sets of genes determines some of the body features, characteristics or traits. The genes in the body form the genotype and the genotype is expressed physically which is now the phenotype i.e traits expressed physically in the body which is an indication of body appearance.
On a clear cloudless day, the sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we visually perceive red and orange colors because the blue light has been scattered out and away from the line of optical discernment.
Hope this helps! :)