Answer:
The magnetic force on a current-carrying wire is perpendicular to both the wire and the magnetic field with direction given by the right hand rule.
<u>Answer:</u>
To support the idea that all living things are composed of cells samples of many kinds of living things should be examined under a microscope to identify the presence of cells.
<u>Explanation:</u>
Cell theory states that all living beings are composed of cells. To prove this a thorough examination of a number of living beings under a powerful microscope is needed. Parts of all living things when observed under the microscope are found to be made up of smaller units called cells.
This examination helps to identify differences between plant cells and animal cells. It also gives an idea of the existence of unicellular organisms.
What mass of water must fall 12m in order to lose 10,800J of gravitational potential energy ?
Potential energy = (mass) x (gravity) x (height)
10,800J = (mass) x (9.8 m/s²) x (12m)
Mass = (10,800J) / (9.8 m/s² x 12m)
Mass = (10,800 / 9.8 x 12) (Joule-sec²/m²)
(Units: Joule-sec²/m² = N-m-sec²/m² = (kg-m/s²)-m-sec²/m² = <u><em>kg </em></u>)
<u>Mass = 91.8 kg</u>
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
