Young's modulus for a rod is 4 X 4x10 to the 11th power. what strain will be produced by a tensile stress of 420 MPa? I don't know where to start with this...

To determine the strain produced by a given tensile stress using Young's modulus, we can use the formula:

Strain = Stress / Young's Modulus

First, it is important to note that the Young's modulus you have provided, 4 x 10^11, appears to be missing a unit. Young's modulus is usually measured in pascals (Pa) or megapascals (MPa), so it might be helpful to clarify the unit.

In this case, assuming the Young's modulus is in megapascals (MPa), and the tensile stress is given as 420 MPa, we can proceed with the calculation.

Step 1: Convert the tensile stress from MPa to Pa:
1 MPa = 1 x 10^6 Pa, so 420 MPa = 420 x 10^6 Pa = 4.2 x 10^8 Pa.

Step 2: Calculate the strain using the formula:
Strain = Stress / Young's Modulus

Strain = (4.2 x 10^8 Pa) / (4 x 10^11 Pa) = 1.05 x 10^-3

Therefore, the strain produced by a tensile stress of 420 MPa, with a Young's modulus of 4 x 10^11 Pa, is approximately 1.05 x 10^-3.