LATEST PRAXIS PHYSICS: CONTENT
KNOWLEDGE (5265) BY ETS
CERTIFICATION EXAM | Q&A WITH
RATIONALES
1. A particle moves along a straight line such that its
position as a function of time is given by x(t) = 4t² − 2t
+ 1 (in meters). What is the particle's velocity at t = 2
seconds?
A) 10 m/s
B) 14 m/s
C) 16 m/s
D) 18 m/s
Correct answer: B
Rationale: Velocity is the derivative of position with
respect to time, v(t) = dx/dt = 8t − 2. At t = 2 s, v = 8(2)
− 2 = 14 m/s.
2. A 5 kg box is at rest on a horizontal frictionless
surface. A constant horizontal force of 20 N is
applied. What is the acceleration of the box?
,A) 2 m/s²
B) 4 m/s²
C) 5 m/s²
D) 10 m/s²
Correct answer: B
Rationale: Using Newton's second law, F = ma, so a =
F/m = 20/5 = 4 m/s².
3. A ball is thrown vertically upward with an initial
speed of 30 m/s. Ignoring air resistance, what is the
maximum height reached by the ball? (Use g = 10
m/s²)
A) 30 m
B) 45 m
C) 60 m
D) 90 m
Correct answer: B
Rationale: At maximum height, v² = u² + 2as, with v =
0, u = 30 m/s, and a = −10 m/s². Solving 0 = 900 − 20s
gives s = 45 m.
,4. Which of the following quantities is a vector?
A) Speed
B) Distance
C) Displacement
D) Mass
Correct answer: C
Rationale: Displacement is a vector quantity because
it has both magnitude and direction. Speed,
distance, and mass are scalars.
5. A 2 kg object moving at 4 m/s collides elastically
with a stationary 6 kg object. What is the velocity of
the 6 kg object after the collision?
A) 1 m/s
B) 2 m/s
C) 3 m/s
D) 4 m/s
Correct answer: B
Rationale: In an elastic collision, both momentum and
kinetic energy are conserved. Using conservation of
momentum and kinetic energy for a one-dimensional
, elastic collision: v₂' = (2m₁/(m₁ + m₂))v₁ =
(2*2/(2+6))*4 = (4/8)*4 = 2 m/s.
6. A force of 50 N is applied at the end of a wrench
0.4 m long, perpendicular to the wrench. What is the
magnitude of the torque?
A) 10 N·m
B) 20 N·m
C) 30 N·m
D) 40 N·m
Correct answer: B
Rationale: Torque τ = rFsinθ. Since the force is
perpendicular, sinθ = 1. τ = 0.4 × 50 = 20 N·m.
7. A 10 kg block is suspended from a spring scale.
The scale reads 80 N. What is the acceleration of the
block? (Use g = 10 m/s²)
A) 2 m/s² upward
B) 2 m/s² downward
C) 8 m/s² upward
KNOWLEDGE (5265) BY ETS
CERTIFICATION EXAM | Q&A WITH
RATIONALES
1. A particle moves along a straight line such that its
position as a function of time is given by x(t) = 4t² − 2t
+ 1 (in meters). What is the particle's velocity at t = 2
seconds?
A) 10 m/s
B) 14 m/s
C) 16 m/s
D) 18 m/s
Correct answer: B
Rationale: Velocity is the derivative of position with
respect to time, v(t) = dx/dt = 8t − 2. At t = 2 s, v = 8(2)
− 2 = 14 m/s.
2. A 5 kg box is at rest on a horizontal frictionless
surface. A constant horizontal force of 20 N is
applied. What is the acceleration of the box?
,A) 2 m/s²
B) 4 m/s²
C) 5 m/s²
D) 10 m/s²
Correct answer: B
Rationale: Using Newton's second law, F = ma, so a =
F/m = 20/5 = 4 m/s².
3. A ball is thrown vertically upward with an initial
speed of 30 m/s. Ignoring air resistance, what is the
maximum height reached by the ball? (Use g = 10
m/s²)
A) 30 m
B) 45 m
C) 60 m
D) 90 m
Correct answer: B
Rationale: At maximum height, v² = u² + 2as, with v =
0, u = 30 m/s, and a = −10 m/s². Solving 0 = 900 − 20s
gives s = 45 m.
,4. Which of the following quantities is a vector?
A) Speed
B) Distance
C) Displacement
D) Mass
Correct answer: C
Rationale: Displacement is a vector quantity because
it has both magnitude and direction. Speed,
distance, and mass are scalars.
5. A 2 kg object moving at 4 m/s collides elastically
with a stationary 6 kg object. What is the velocity of
the 6 kg object after the collision?
A) 1 m/s
B) 2 m/s
C) 3 m/s
D) 4 m/s
Correct answer: B
Rationale: In an elastic collision, both momentum and
kinetic energy are conserved. Using conservation of
momentum and kinetic energy for a one-dimensional
, elastic collision: v₂' = (2m₁/(m₁ + m₂))v₁ =
(2*2/(2+6))*4 = (4/8)*4 = 2 m/s.
6. A force of 50 N is applied at the end of a wrench
0.4 m long, perpendicular to the wrench. What is the
magnitude of the torque?
A) 10 N·m
B) 20 N·m
C) 30 N·m
D) 40 N·m
Correct answer: B
Rationale: Torque τ = rFsinθ. Since the force is
perpendicular, sinθ = 1. τ = 0.4 × 50 = 20 N·m.
7. A 10 kg block is suspended from a spring scale.
The scale reads 80 N. What is the acceleration of the
block? (Use g = 10 m/s²)
A) 2 m/s² upward
B) 2 m/s² downward
C) 8 m/s² upward
