Strategic Approach with Modern Physics 5th Edition
2026/2027 | Randall D. Knight Physics Test Bank,
Study Guide, Practice Questions & Answers,
Introductory Calculus-Based Physics Exam Prep,
Newton’s Laws, Kinematics, Vectors, Dynamics, Work
& Energy, Momentum, Rotation, Gravitation, Fluids,
Oscillations, Waves, Thermodynamics, Electricity,
Magnetism, Optics, Relativity, Quantum Physics,
Atomic Physics & Detailed Rationales
Question 1: Which of the following best defines a "particle" as the
term is used in physics?
A. Any object with a mass greater than 1 kg
B. An object whose size and shape are irrelevant to the analysis of its
motion
C. A small object that is always spherical in shape
D. Any object that is too small to be seen with the naked eye
CORRECT ANSWER: B. An object whose size and shape are
irrelevant to the analysis of its motion
Rationale: In physics, a particle is an idealized model where the object's
internal structure, size, and shape are neglected because they do not
significantly affect the problem being analyzed. The key criterion is the
irrelevance of internal dimensions to the motion, not the physical size or
mass of the object.
Question 2: A quantity that has both magnitude and direction is
called a:
A. Scalar
B. Vector
C. Tensor
D. Complex number
CORRECT ANSWER: B. Vector
Rationale: A vector quantity is defined by having both a magnitude (how
much) and a direction (which way). Scalars have magnitude only. Tensors
are more complex mathematical objects used in advanced physics.
,Question 3: You walk 3.0 m east, then 4.0 m north. What is the
magnitude of your displacement from the starting point?
A. 1.0 m
B. 5.0 m
C. 7.0 m
D. 12.0 m
CORRECT ANSWER: B. 5.0 m
Rationale: Displacement is the straight-line vector from start to finish. Using
the Pythagorean theorem: √(3.0² + 4.0²) = √(9 + 16) = √25 = 5.0 m. The
path length walked is 7.0 m, but displacement magnitude is 5.0 m.
Question 4: If an object's velocity is constant, what must be true
about its acceleration?
A. Acceleration is constant but non-zero
B. Acceleration is zero
C. Acceleration is increasing
D. Acceleration is negative
CORRECT ANSWER: B. Acceleration is zero
Rationale: Acceleration is defined as the rate of change of velocity. If
velocity is constant (unchanging in both magnitude and direction), then the
rate of change is zero, so acceleration must be zero.
Question 5: A car accelerates uniformly from 10 m/s to 30 m/s in
5.0 seconds. What is its acceleration?
A. 2.0 m/s²
B. 4.0 m/s²
C. 6.0 m/s²
D. 8.0 m/s²
CORRECT ANSWER: B. 4.0 m/s²
Rationale: Acceleration = change in velocity / time = (30 m/s − 10 m/s) /
5.0 s = 20 m/s / 5.0 s = 4.0 m/s².
Question 6: An object is dropped from rest. Neglecting air
resistance, how far does it fall in 3.0 seconds? (g = 9.8 m/s²)
,A. 14.7 m
B. 29.4 m
C. 44.1 m
D. 88.2 m
CORRECT ANSWER: C. 44.1 m
Rationale: For an object dropped from rest: y = ½gt² = ½(9.8 m/s²)(3.0 s)²
= ½(9.8)(9.0) = 44.1 m.
Question 7: Which of the following is a vector quantity?
A. Mass
B. Temperature
C. Speed
D. Velocity
CORRECT ANSWER: D. Velocity
Rationale: Velocity is a vector because it includes both magnitude (speed)
and direction. Mass, temperature, and speed are all scalar quantities with
magnitude only.
Question 8: A ball is thrown straight up with an initial speed of 20
m/s. What is its speed at the highest point?
A. 20 m/s
B. 10 m/s
C. 0 m/s
D. Cannot be determined
CORRECT ANSWER: C. 0 m/s
Rationale: At the highest point of vertical motion, the ball momentarily
stops before reversing direction. The velocity is zero at the peak, though
the acceleration remains 9.8 m/s² downward throughout.
Question 9: The slope of a position-versus-time graph gives:
A. Acceleration
B. Velocity
C. Displacement
D. Distance traveled
CORRECT ANSWER: B. Velocity
, Rationale: The derivative of position with respect to time is velocity.
Geometrically, this is the slope of the position-time graph at any point.
Question 10: Which kinematic equation correctly relates velocity,
acceleration, and displacement?
A. v = v₀ + at
B. x = x₀ + v₀t + ½at²
C. v² = v₀² + 2a(x − x₀)
D. All of the above are correct
CORRECT ANSWER: D. All of the above are correct
Rationale: All three are standard constant-acceleration kinematic equations.
Option A relates velocity and time; B relates position and time; C relates
velocity and position without requiring time.
Question 11: Newton's first law is also known as the law of:
A. Acceleration
B. Inertia
C. Action-reaction
D. Universal gravitation
CORRECT ANSWER: B. Inertia
Rationale: Newton's first law states that an object at rest stays at rest and an
object in motion stays in motion with constant velocity unless acted upon
by a net external force. This property of resisting changes in motion is
called inertia.
Question 12: A net force of 20 N acts on a 4.0 kg object. What is the
acceleration?
A. 0.20 m/s²
B. 5.0 m/s²
C. 16 m/s²
D. 80 m/s²
CORRECT ANSWER: B. 5.0 m/s²
Rationale: Newton's second law: a = F_net / m = 20 N / 4.0 kg = 5.0 m/s².
Question 13: Which of the following is NOT a contact force?