Rio Salado PHY 111 Final Most Recent
Version Comprehensive 80 Questions and
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Section 1: Energy, Work, and Power (Questions 1-15)
Q1: How much energy is stored in a spring that has been
compressed 0.20 m if the spring constant is 300 N/m?
A. 3 J
B. 6 J
C. 12 J
D. 60 J
Answer: B. 6 J
Rationale: The formula for spring potential energy is PE = ½kx².
Plugging in: PE = ½(300 N/m)(0.20 m)² = ½(300)(0.04) = ½(12) = 6 J.
Q2: A student pushes a 0.2 kg box against a spring causing the
spring to compress 0.15 m. When the spring is released, it will
launch the box vertically into the air. What is the maximum height
the box will reach if the spring constant is 300 N/m?
,A. 0.85 m
B. 1.7 m
C. 3.4 m
D. 6.8 m
Answer: B. 1.7 m
Rationale: Energy conservation: Spring PE converts to gravitational PE.
½kx² = mgh → h = (kx²)/(2mg) = (300 × 0.0225)/(2 × 0.2 × 9.8) =
(6.75)/(3.92) ≈ 1.7 m.
Q3: Power is best defined as:
A. The ability to do work
B. The rate of energy transfer
C. The force applied over a distance
D. The product of mass and velocity
Answer: B. The rate of energy transfer
Rationale: Power is defined as the rate at which work is done or energy
is transferred. The SI unit is the watt (W), which equals one joule per
second.
Q4: A car travels at a constant speed up a hill from point A to point
B. Which of the following statements is most correct?
A. The gravitational potential energy decreases, and the kinetic energy
increases
,B. The gravitational potential energy increases, and the kinetic energy
decreases
C. The gravitational potential energy increases, and the kinetic energy
remains the same
D. Both gravitational potential energy and kinetic energy remain the
same
Answer: C. The gravitational potential energy increases, and the
kinetic energy remains the same
Rationale: As the car goes up the hill, height increases so gravitational
potential energy (mgh) increases. Since speed is constant, kinetic energy
(½mv²) remains unchanged.
Q5: A student connects a 1 hp motor to a bicycle. How much time
will it take for the bicycle to accelerate from rest to a speed of 5.0
m/s if the combined mass of the student and the bicycle is 120 kg? (1
hp = 746 W)
A. 0.5 sec
B. 1 sec
C. 2 sec
D. 4 sec
Answer: C. 2 sec
, Rationale:
Work-energy theorem: Power × time = change in kinetic
energy. 746W × t = ½(120 kg)(5 m/s)² → 746t = ½(120)(25) = 1500 → t
= 1500/746 ≈ 2 seconds.
Q6: What is the horsepower required for a 1200 kg car to travel
from rest to a speed of 20 m/s in 7.0 seconds? (746 W = 1 hp)
A. 23 hp
B. 32 hp
C. 46 hp
D. 64 hp
Answer: C. 46 hp
Rationale: First find kinetic energy: KE = ½(1200 kg)(20 m/s)² = 600 ×
400 = 240,000 J. Power = Energy/time = 240,000/7.0 ≈ 34,286 W.
Convert to hp: 34,286/746 ≈ 46 hp.
Q7: Energy is best defined as:
A. The force required to move an object
B. The ability to make a system change in some way
C. The product of mass and acceleration
D. The rate at which work is done
Answer: B. The ability to make a system change in some way
Energy is the capacity to do work or cause change in a
Version Comprehensive 80 Questions and
Answers Accurate Solutions
Already Graded A+ Get it 100% Correct .
Section 1: Energy, Work, and Power (Questions 1-15)
Q1: How much energy is stored in a spring that has been
compressed 0.20 m if the spring constant is 300 N/m?
A. 3 J
B. 6 J
C. 12 J
D. 60 J
Answer: B. 6 J
Rationale: The formula for spring potential energy is PE = ½kx².
Plugging in: PE = ½(300 N/m)(0.20 m)² = ½(300)(0.04) = ½(12) = 6 J.
Q2: A student pushes a 0.2 kg box against a spring causing the
spring to compress 0.15 m. When the spring is released, it will
launch the box vertically into the air. What is the maximum height
the box will reach if the spring constant is 300 N/m?
,A. 0.85 m
B. 1.7 m
C. 3.4 m
D. 6.8 m
Answer: B. 1.7 m
Rationale: Energy conservation: Spring PE converts to gravitational PE.
½kx² = mgh → h = (kx²)/(2mg) = (300 × 0.0225)/(2 × 0.2 × 9.8) =
(6.75)/(3.92) ≈ 1.7 m.
Q3: Power is best defined as:
A. The ability to do work
B. The rate of energy transfer
C. The force applied over a distance
D. The product of mass and velocity
Answer: B. The rate of energy transfer
Rationale: Power is defined as the rate at which work is done or energy
is transferred. The SI unit is the watt (W), which equals one joule per
second.
Q4: A car travels at a constant speed up a hill from point A to point
B. Which of the following statements is most correct?
A. The gravitational potential energy decreases, and the kinetic energy
increases
,B. The gravitational potential energy increases, and the kinetic energy
decreases
C. The gravitational potential energy increases, and the kinetic energy
remains the same
D. Both gravitational potential energy and kinetic energy remain the
same
Answer: C. The gravitational potential energy increases, and the
kinetic energy remains the same
Rationale: As the car goes up the hill, height increases so gravitational
potential energy (mgh) increases. Since speed is constant, kinetic energy
(½mv²) remains unchanged.
Q5: A student connects a 1 hp motor to a bicycle. How much time
will it take for the bicycle to accelerate from rest to a speed of 5.0
m/s if the combined mass of the student and the bicycle is 120 kg? (1
hp = 746 W)
A. 0.5 sec
B. 1 sec
C. 2 sec
D. 4 sec
Answer: C. 2 sec
, Rationale:
Work-energy theorem: Power × time = change in kinetic
energy. 746W × t = ½(120 kg)(5 m/s)² → 746t = ½(120)(25) = 1500 → t
= 1500/746 ≈ 2 seconds.
Q6: What is the horsepower required for a 1200 kg car to travel
from rest to a speed of 20 m/s in 7.0 seconds? (746 W = 1 hp)
A. 23 hp
B. 32 hp
C. 46 hp
D. 64 hp
Answer: C. 46 hp
Rationale: First find kinetic energy: KE = ½(1200 kg)(20 m/s)² = 600 ×
400 = 240,000 J. Power = Energy/time = 240,000/7.0 ≈ 34,286 W.
Convert to hp: 34,286/746 ≈ 46 hp.
Q7: Energy is best defined as:
A. The force required to move an object
B. The ability to make a system change in some way
C. The product of mass and acceleration
D. The rate at which work is done
Answer: B. The ability to make a system change in some way
Energy is the capacity to do work or cause change in a
