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 answer is a) The kinetic energy of the ice increases by equal amounts for equal distances.
Explanation:
The law of conservation states that the energy cannot be created nor be destroyed but can be converted from one form to another.Before the ice even starts falling we already know that it possesses energy in the form of potential energy given by P=mgh where m is the mass of the ice , g is the acceleration due to gravity and h is the height of the ice above the ground whatever that may be, since a number is not given here.As the ice falls the energy is converted from potential energy to kinetic energy. We notice one thing about the equation for the potential energy P , which is that it is not only directly proportional to h but also is linear in h as well(which is the main reason why a) is correct) which means that if the ice drops by 1 meter the potential energy it will have lost would be ΔPE=mgΔh=-mg, where Δh is the change in its height which is 1 meter here.And according to the principle of conservation of energy this energy must be converted to kinetic energy so the ΔKE=-ΔPE=mg, and this process repeats and for each meter it falls, it picks up the same amount of kinetic energy equaling mg(which is the same as the loss in PE per each meter of fall). So a 2 meter decrease in height will result in an increase in KE of 2mg, a 3 meter decrease in height will result in an increase in KE of 3mg. gain in kinetic energy only depends on the drop in height, which is true irrespective of where the ice might happen to be in its journey close to the top or the bottom. So the drop in height of lets say x at any point in the journey will result in the same increase in KE = ΔKE = mgx. Which proves part a) to be correct.
The metal ball lost energy while the putty ball gained energy.
<h3>What is momentum?</h3>
Momentum is the product of mass and velocity of the body. We must note that momentum before collision is equal to momentum after collision.
1) Kinetic energy before collision = 1/2mv^2 = 0.5 * 6 * 4 = 12 J
2) kinetic energy after collision = 0.5 * 6 * 2= 6 J
3) Kinetic energy of putty ball = 0.5 * 6 * 2= 6 J
4) Energy lost by the metal ball = 12 J - 6 J = 6 J
5) Energy gained by the putty ball = 6 J - 0J = 6 J
6) The rest of the energy was converted to heat after the collision.
Learn more about kinetic energy: brainly.com/question/999862
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Answer:
=20 turns
Explanation:
The given case is a step down transformer as we need to reduce 120 V to 6 V.
number of turns on primary coil N_{P}= 400
current delivered by secondary coil I_{S}= 500 mA
output voltage = 6 V (rms)
we know that
putting values we get
to calculate number of turns in secondary
therefore, =20 turns
