Stress

Define ‘stress’.

applied force per unit cross-sectional area that causes deformation

What is tensile stress?

force applied perpendicular to surface area object ends, increase object’s length

What is compressive stress?

force applied perpendicular to surface area object ends, decrease object’s length

What is strain?

ratio between the changed length and the natural length

What happens after tension exceeds the elastic limit?

any deformation is permanent as object cannot restore back to its natural length even after the tension is removed.

What is Young’s modulus?

measure of the stiffness of the material

What happens in a greenstick fracture?

A greenstick fracture occurs when a bone bends and cracks, instead of breaking completely.

What is the Shear’s modulus?

when the force applied is tangential or parallel to the surface area

A metal wire 1.0 mm in diameter and 2.0 m long hangs vertically with a 6.0 kg mass suspended from it. If the wire stretches 1.4 mm under the tension, what is the value of Young’s modulus for the metal?

1.1 x 10¹¹ Pa

A 50 kg mass is suspended from a cable with a diameter of 2.0 cm. What is the stress on the cable?

1.6MPa