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
To determine the distance that you would travel by.
Simply convert 15 minutes to seconds which would be 900 seconds.
Then solve for distance, which would be
D = r • t
D = 12 m/s • 900 s
D =10 800 m.
This is the distance that you had ran for.
Answer:
D. Validity group
Explanation:
A validity group is not necessarily a component of a normal experiment.
A normal experiment is made up of the dependent variables, independent variables, and most times the control group.
- The dependent variable is one that relies on the outcome of the effect produced from the experimental design
- The independent variable is the one that causes a desired effect under the study.
- The control group is a group that does not receive any treatment nor attenuation of the conditions.
Oil, plexiglass, then water
Answer:
The correct option is (c).
Explanation:
When an object tied to a rope and we rotate it, the centripetal force acting on it. This force acts towards the center of the circle. The magnitude of the force is given by :
Where,
m is mass, v is speed and r is radius of path
If the length of the rope is increased, it means it will make a large circle i.e. large radius.
As we can see that force is inversely proportional to the radius of circle. It means less force is required because the force is inversely proportional to the radius of the circular orbit. Hence, the correct option is (c).