A plate of an alloy steel has a plane-strain fracture toughness of 50 MPa-m1/2. If it is known that the largest surface crack is 0.5 mm long, and that the value of Y is 1.1, which of the following can be said about this plate when a tensile stress of 1200 MPa is applied? a. It is not possible to determine whether or not the plate will fracture.
b. The plate will definitely not fracture.
c. The plate will definitely fracture.

Option C (The plate will definitely fracture) is the correct option.

Explanation:

According to the question,

The critical stress will be:

⇒

By putting the values, we get

So,

Thus, the above is the correct response.

first let us lay out the formula for potential

and kinetic energy:

pe = mgh

ke = (mv^2)/2

where: m=mass, v=velocity, g=gravitational

acceleration, h=height

calculating for mass using the known values of

pe:

340j = m (9.81 m/s^2) (50ft) (1m/3.28ft)

m = 2.27 kg

the law of conservation of energy states that

energy is neither created nor destroyed. therefore, the change in kinetic

energy from 50 ft to 35 ft would be equal to the change in potential energy

from 50 ft to 35 ft. however it would be opposite in signs since one is losing

while other is gaining.

ke(35ft) – ke(50ft) = - [ pe(35ft) – pe(50ft]

ke(50ft) = 0 since the brick is initially at rest

ke(35ft) = 340j - 2.27kg (9.81 m/s^2) (35ft)

(1m/3.28 ft)

ke(35ft)

= 102.38 j

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).