Explanation:
Given data:
d = 30 mm = 0.03 m
L = 1m 
S = 70 Mpa
 = 70 Mpa
Δd = -0.0001d
Axial force = ?
validity of elastic deformation assumption.
Solution:
O'₂ = Δd/d = (-0.0001d)/d = -0.0001
For copper,
v = 0.326      E = 119×10³ Mpa
O'₁ = O'₂/v = (-0.0001)/0.326 = 306×10⁶
∵δ = F.L/E.A    and σ = F/A so,
σ = δ.E/L = O'₁ .E = (306×10⁻⁶).(119×10³) = 36.5 MPa
F = σ . A = (36.5 × 10⁻⁶) . (π/4 × (0.03)²) = 25800 KN
S = 70 MPa > σ = 36.5 MPa
 = 70 MPa > σ = 36.5 MPa
∵ elastic deformation assumption is valid.
so the answer is
F = 25800 K N            and     S > σ
 > σ
 
        
             
        
        
        
Answer:

Explanation:
Height of the cliff is given as

now the time taken by the diver to hit the surface is given as



Now in the same time it has to cover a distance of 13.39 m
so the speed in horizontal direction is given as



 
        
             
        
        
        
The natural light display called aurora borealis is located in the northern 
hemisphere.
There are two types of aurora which are called aurora borealis and aurora 
australis. The aurora borealis is located in the Northern hemisphere while 
the aurora australis is located in the Southern hemisphere.
They receive their energy through the interaction of charged particles 
on the Sun and Earth to produce the light display. An example 
of the interaction involves solar wind with atoms of the upper atmosphere. 
Read more on brainly.com/question/20191244
 
        
             
        
        
        
It's 100% false, it wastes a ton (sorry for the bad pun!) of gas.
 
        
                    
             
        
        
        
False , because collinear points lie on a line not on a plane.
Coplanar points on the other hand, lie on a plane.