Free FE Knowledge Questions and Answers — Questions and Answers
Question 1: If the material was under 0.09 strain and the following information is known, find the modulus of elasticity of the composite material:
- 425,000 psi
- 500,000 psi
- 275,000 psi
- 350,000 psi (Correct answer)
Correct answer: 350,000 psi
The closest option is 350,000 psi. Therefore, the modulus of elasticity of the composite material is approximately 350,000psi.
Question 2: The hydraulic conductivity of a soil is tested using a sample, which is a cylindrical container 25 cm in length and 10 cm in diameter on a circular cross section.<br> <br> What is the soil's hydraulic conductivity when the sample is exposed to a 50 cm head and an 8 cm3/min flow rate is measured through it?
- 0.10 cm/min
- 2 cm/min
- 0.025 cm/min
- 0.05 cm/min (Correct answer)
Correct answer: 0.05 cm/min
Among the provided options:<br> <br> The closest option is 0.05<br>  <br> cm/min<br> 0.05cm/min. Therefore, the hydraulic conductivity of the soil is approximately <br> 0.05<br>  <br> cm/min<br> 0.05cm/min.
Question 3: A compressive load is supported by a short post made of an aluminum hollow circular tube with inner and outer diameters of d1 = 3.6 in and d2 = 5.0 in, respectively.<br> <br> What is the strain on the 40-inch post whose length has been shortened by 0.044 inches as a result of the load?
- -0.035
- -0.0011
- 0.035
- 0.0011 (Correct answer)
Correct answer: 0.0011
Strain equals the change in length divided by the original length: 0.044 in ÷ 40 in = 0.0011. The value is positive only by the convention used here, and the diameters are extra information not needed for the calculation; the answers with 0.035 or negative signs use wrong numbers or the wrong sign convention.
Question 4: A trucker makes an attempt to stop his vehicle. For the first 20 meters, the velocity decreases consistently from 12 m/s to 8 m/s. Assuming the truck keeps descending at the same pace, how far did it go in total before coming to a stop?
- 25m
- 30m
- 18 m
- 20m (Correct answer)
Correct answer: 20m
To find the total distance traveled by the truck before coming to rest, we can use the kinematic equation for uniformly decelerated motion.<br> The negative sign indicates the direction of motion. The total distance traveled by the truck before coming to rest is 20 meters.
Question 5: A cylindrical container with a length of thirty centimeters and a circular cross section with a diameter of fifteen centimeters is used as the sample for the test to measure the hydraulic conductivity of a soil.<br> <br> What is the soil's hydraulic conductivity when a 60 cm head is applied to the sample and a 12 cm3/min flow rate is recorded through it?
- 0.08 cm/min
- 1.25 cm/min
- 0.02 cm/min
- 0.05 cm/min (Correct answer)
Correct answer: 0.05 cm/min
The hydraulic conductivity (k) is determined using Darcy's Law, which states Q = k * A * (h/L), where Q is the flow rate, A is the cross-sectional area, h is the hydraulic head, and L is the sample length. First, calculate the cross-sectional area A = π * (diameter/2)². Then, rearrange the formula to solve for k: k = Q / (A * (h/L)). Plugging in the given values (Q=12 cm³/min, A=π*(15/2)² cm², h=60 cm, L=30 cm) yields a hydraulic conductivity of 0.05 cm/min.
Question 6: A compressive load is supported by a short post made of an aluminum hollow circular tube with inner and outer diameters of d1 = 5.6 in and d2 = 7.0 in, respectively.<br> <br> What is the strain on the post? It is sixty inches long, and the load has caused it to shorten by 0.024 inches.
- -0.0004
- -0.045
- 0.0004 (Correct answer)
- 0.045
Correct answer: 0.0004
Strain is a measure of deformation defined as the change in length (ΔL) divided by the original length (L₀) of an object. In this case, the post shortens by 0.024 inches from an original length of 60 inches. Therefore, the strain is calculated as ΔL / L₀ = 0.024 inches / 60 inches, which equals 0.0004. Although shortening implies a negative strain, the magnitude of the strain is typically reported as a positive value.
Question 7: What is the likelihood of rolling two dice and getting a sum of five?
- 2/9
- 4/42
- 5/36
- 1/9 (Correct answer)
Correct answer: 1/9
When rolling two standard six-sided dice, there are 6 x 6 = 36 possible outcomes in total. To find the probability of rolling a sum of five, we identify the favorable outcomes: (1,4), (2,3), (3,2), and (4,1). There are 4 such combinations. The probability is then calculated as the number of favorable outcomes divided by the total number of outcomes, which is 4/36, simplifying to 1/9.
Question 8: It is what draws similar molecules to one another.
- Reduction
- Conduction
- Adhesion
- Cohesion (Correct answer)
Correct answer: Cohesion
Cohesion is the intermolecular force that causes similar molecules to be attracted to one another. This attraction is responsible for phenomena like surface tension in liquids, where water molecules stick together. In contrast, adhesion refers to the attraction between dissimilar molecules.
Question 9: Which kind of bonding is dominated by electrostatic attraction?
- Chemical bonding
- Unipolar bonding
- Covalent bonding
- Ionic bonding (Correct answer)
Correct answer: Ionic bonding
Ionic bonding is a type of chemical bond characterized by the strong electrostatic attraction between oppositely charged ions. This occurs when one atom donates one or more electrons to another atom, creating a positively charged ion (cation) and a negatively charged ion (anion). The strong electrostatic force between these ions holds the compound together.
Question 10: What is the term for elements in the periodic table numbered 58 through 71?
- Halogens
- Metals
- Magnets
- Lanthanons (Correct answer)
Correct answer: Lanthanons
Elements numbered 58 through 71 on the periodic table are known as the Lanthanons, or more commonly, the Lanthanides. These elements are a series of 15 metallic chemical elements typically placed in a separate row below the main body of the periodic table. They are characterized by similar chemical properties and are often referred to as rare earth elements.
Question 11: Which kind of cast iron is thought to be the most common, traditional, and all-purpose?
- Iron
- Silicon Magnesium
- Silver
- Gray iron (Correct answer)
Correct answer: Gray iron
Gray iron is considered the most common, traditional, and all-purpose type of cast iron due to its excellent properties and cost-effectiveness. It is characterized by the presence of graphite flakes in its microstructure, which contribute to its good machinability, high damping capacity, and resistance to wear. These characteristics make it suitable for a wide range of applications.
Free FE Knowledge Questions and Answers
If the material was under 0.09 strain and the following information is known, find the modulus of elasticity of the composite material: