Answer:
275 MPa, -175 MPa
-0.63636
450 MPa
Explanation:
= Maximum stress
= Minimum stress
= Mean stress = 50 MPa
= Stress amplitude = 225 MPa
Mean stress is given by

Stress amplitude is given by


Maximum stress level is 275 MPa
Minimum stress level is -175 MPa
Stress ratio is given by

The stress ratio is -0.63636
Stress range is given by

Magnitude of the stress range is 450 MPa
Answer:
18375g
Explanation:


Let's find the volume of the rectangular block.
Volume
= length ×breadth ×height
= 3.5 ×6 ×2.5
= 52.5cm³
Mass of the block
= 350(52.5)
= 18375g
F = G Mm/r²
mg = G Mm/r²
g = GM/r²
At centre of earth, r=0
g = GM/0
g =0