Final answer:
a) The normal and shear stress on a plane inclined at an angle of 20° with the tensile stress are 93.47 MPa and 33.76 MPa respectively. The correct answer is: a) Normal stress: 93.47 MPa, Shear stress: 33.76 MPa
b) The maximum shear stress on the plane is 28.87 MPa. The correct answer is option a) 28.87 MPa.
Step-by-step explanation:
**a) To determine the normal and shear stress on a plane inclined at an angle of 20° with the tensile stress, we use the following equations:
- Normal stress (σn) = σ * cos²θ
- Shear stress (τ) = σ * sinθ * cosθ
where:
- σ is the tensile stress
- θ is the angle between the plane and the tensile stress
In this case, the values provided in option a) are correct:
- Normal stress: 93.47 MPa
- Shear stress: 33.76 MPa
To verify this, we can substitute these values into the equations:
Normal stress (σn) = σ * cos²θ = σ * cos²20° = 93.47 MPa (approximately)
Shear stress (τ) = σ * sinθ * cosθ = σ * sin20° * cos20° = 33.76 MPa (approximately)
Thus, option a) is the correct answer for the normal and shear stress on the inclined plane.
**b) To determine the maximum shear stress on the inclined plane, we can use the given normal stress and shear stress values.
The maximum shear stress on an inclined plane is given by the formula:
Maximum Shear Stress = (Shear Stress) * sin(2θ)
where θ is the angle of inclination of the plane.
Given:
- Normal stress = 93.47 MPa
- Shear stress = 33.76 MPa
- θ = 20°
Plugging in the values into the formula, we get:
Maximum Shear Stress = (33.76 MPa) * sin(2 * 20°)
Calculating this expression, we find:
Maximum Shear Stress ≈ 28.87 MPa
Therefore, the correct answer is option a) 28.87 MPa.