Chemistry
What are the MINIMUM coefficients needed to balance this equation?
C3H5N3O9+H2O+H2SO4
(A) 2, 6, 2, 2, 6, 2
(B) 1, 3, 3, 1, 3, 2
(C) 4, 2, 1, 1, 2, 4
(D) 1, 3, 1,
(D) 1, 3, 1, 1, 3, 1
A body is in static equilibrium. Which of the following must be true?
(A) The sum of the forces acting on the body is zero.
(B) The some of moments about any point is zero
(C) The body is moving at constant velocity
(D) Both A and B
(D) Both A and B
Which of the following material properties best describes a material’s ability to resist deformation under load?
a) Toughness
b) Ductility
c) Elastic modulus
d) Poisson’s ratio
c) Elastic modulus
Which of the following is true for a closed system undergoing an adiabatic process?
a) No work crosses the system boundary
b) Heat transfer occurs freely
c) No heat crosses the system boundary
d) The pressure remains constant
c) No heat crosses the system boundary
What is the decimal equivalent of the 8-bit binary number 11010110?
a) 214
b) 208
c) 198
d) 182
(a) 214
Work Shown:
1⋅2^7+1⋅2^6+0⋅2^5+1⋅2^4+0⋅2^3+1⋅2^2+1⋅2^1+0⋅2^0=128+64+16+4+2=214
An unkown quantity of hydrogen gas has a volume of 2.5 L at STP (0°C and 1 atm). What is the mass of hydrogen? (R = 0.08206 atm L/ mol K) (MW of H2 = 2.0158 g/mol)
(A) 0.073 g
(B) 0.19 g
(C) 0.22 g
(D) 0.51 g
(C) 0.22 g
Work Shown:
n = (1 atm)(2.5 L)/(0.08206 atm L/ mol K)(273K) = 0.1116 mol mass = (0.1116 mol)(2)(1.0079g/mol) = 0.225g
A beam is in equilibrium and supports two downward forces: 5 N at 2 m from the left end, and 10 N at 6 m from the left end. What is the reaction force at the left support if the beam is simply supported at both ends (8 m total span)
(A) 5.06 N
(B) 7.5 N
(C) 8.2 N
(D) 6.25 N
(D) 6.25 N
Shown Work:
F = ((5 N x 6 m)+(10 N x 2 m))/8m = 6.25 N
A structural component has a yield strength of 900 MPa and is subjected to a maximum stress of 100 MPa in service. What is the factor of safety (FS) based on yielding?
a) 0.9
b) 900
c) 9
d) 0.09
c)9
Which of the following processes is irreversible?
a) Isothermal heat transfer between two identical reservoirs
b) Expansion of a gas into a vacuum
c) Frictionless adiabatic compression
d) Melting of ice at 0°C in a well-insulated container
b) Expansion of a gas into a vacuum
A 10 Ω resistor has a current of 3 A flowing through it. What is the power dissipated?
a) 10 W
b) 30 W
c) 90 W
d) 100 W
c) 90W
Work Shown:
P=I^2 ⋅R=32⋅10=9⋅10=90 W
The hydro ion concentration of a solution is 1 x 10-7 mole/L. This means that the pH is almost nearly:
(a) 1
(b) 6
(c) 7
(d) 10
(c) 7
Shown Work:
pH = log10 (1/(1*10-7)) = 7
A simply supported beam of length 4 m carries a point load of 100 N at its midpoint. What is the shear force just to the left of the midpoint?
a) 25 N
b) 50 N
c) 100 N
d) 0 N
b) 50 N
Shown Work:
Beam is symmetric, load is centered, so reactions at both ends = 50 N. The only force acting is the reaction = 50 N upward
A metal rod 1.5 m long stretches by 3 mm under a tensile load. What is the engineering strain?
a) 0.0002
b) 0.002
c) 0.02
d) 0.2
a) 0.0002
ΔL / L = 0.003 / 1.5 = 0.0002
Steam enters a turbine at 3 MPa and 400°C and exits at 100 kPa with a velocity of 100 m/s. If heat loss from the turbine is negligible and potential energy changes are ignored, what physical quantity is the turbine primarily designed to extract?
a) Enthalpy
b) Internal energy
c) Kinetic energy
d) Temperature
a) Enthalpy
Which logic gate outputs 1 only when exactly one of the inputs is 1?
a) AND
b) OR
c) XOR
d) NAND
c) XOR
Work Shown:
XOR (exclusive OR) = 1 only when inputs differ (1,0 or 0,1).
Which of the folowing does a catalyst change?
(A) the concentration of product at equilibrium
(B) the equilibrium constant of a reaction
(C) the heat of reaction of a reaction
(D) the activation energy of a reaction
(D) the activation energy of a reaction
In a truss, joint A has two members connected: AB (horizontal) and AC (angled 45° upward to the right). A 100 N load is applied downward at A. What is the force in member AB?
a) 0 N
b) 100 N
c) 141 N
d) 70.7 N
d) 100 N
Work Shown:
Sum of the forces in the Y:
FACsin(45°)=100 ⇒ FAC=100/sin(45°)=141.4N FAB =FACcos(45°)=141.4cos(45°)=100N
A rectangular element is subjected to a normal stress of 60 MPa (tensile) in the x-direction and a shear stress of 40 MPa. What is the magnitude of the maximum shear stress?
a) 20 MPa
b) 40 MPa
c) 50 MPa
d) 60 Mpa
c) 50 MPa
An ideal gas expands isothermally at 300 K from 1.0 m³ to 2.0 m³. If the initial pressure is 100 kPa, what is the work done by the gas?
a) 20.0 kJ
b) 30.5 kJ
c) 69.3 kJ
d) 100.0 kJ
c) 69.3 kJ
Work Shown:
W=P1*V1*ln(V1/V2)=100,000⋅1.0⋅ln(2)≈100,000⋅0.693=69.3kJ
A clock signal with a frequency of 1 MHz is applied to a 3-bit binary counter. What is the frequency at the MSB (most significant bit)?
a) 125 kHz
b) 250 kHz
c) 500 kHz
d) 1 MHz
a) 125 kHz
Work Shown:
fMSB= 1MHz/(2^3)= 1,000,000/ 8 =125,000Hz
How much energy is need to convert ozone to oxygen? DHf(O2) = 0 kcal/mol DHf(O3) = 34.0 kcal/mol
(A) 0 kcal/mol
(B) 34 kcal/mol
(C) 68 kcal/mol
(D) 140 kcal/mol
(A) 0 kcal/mol
Work Shown:
The thermochemical reaction is : 2O3 ® 3O2 +DH The enthalpy of reaction is (3 mol)(0 kcal/mol) - (2 mol)(34.0 kcal/mol) = -68 kcal Since this is negative, reaction is exothermic. No energy is needed.
What is the x-coordinate of the centriod of the areas under the curve y = cos x between x = 0 and x =p/2? dA = y dx
(A) 1 - 2/p
(B) p/2 - 1
(C) p/6
(D) p/4
(B) p/2 - 1
A tensile test is performed on a ductile metal. The material behaves elastically up to a stress of 300 MPa. At 400 MPa, the strain is 0.02. What is the modulus of elasticity (E) and is the material behaving elastically or plastically at 400 MPa?
a)E=600MPa
b) E=20GPa
c) E=125MPa
d) E=1500Pa
b) E=20GPa
E = 400MPa/0.02 = 20 GPa
A 2 kg aluminum block is heated from 25°C to 75°C. If the specific heat of aluminum is 900 J/kg°C, how much heat is added?
a) 45,000 J
b) 90,000 J
c) 135,000 J
d) 180,000 J
b) 90,000 J
Q=mcΔT=2⋅900⋅(75−25)=2⋅900⋅50=90,000J
A voltage divider has resistors R1= 2 ohms R2= 3 ohms connected in series across a 10 V battery. What is the voltage across R2?
a) 3 V
b) 4 V
c) 5 V
d) 6 V
d) 6V
Work Shown:
VR2=Vin⋅(R2/R1+R2)=10⋅(3/2+3)=10⋅3/5 = 6V