AND 100% VERIFIED ANSWERS WITH
RATIONALES GRADED A+ LATEST
LOUISIANA STATE UNIVERSITY
Instructor: William McElgin
Institution: Louisiana State University
Exam Description
This midterm examination assesses student mastery of foundational concepts in
classical mechanics, including kinematics, Newton’s laws of motion, work and
energy, momentum, and basic rotational motion. Questions require conceptual
understanding, quantitative problem-solving, and application of physics principles
to physical situations commonly encountered in laboratory and real-world
contexts.
1. A car accelerates uniformly from rest to a speed of 20 m/s in 10 seconds.
What is the car’s acceleration?
A. 1 m/s²
B. 2 m/s²
C. 10 m/s²
D. 20 m/s²
Correct Answer: B
Rationale: Acceleration is change in velocity divided by time:
a = (20 − 0) / 10 = 2 m/s².
,2. Which quantity is a vector?
A. Speed
B. Distance
C. Displacement
D. Time
Correct Answer: C
Rationale: Displacement includes both magnitude and direction, making it a
vector quantity.
3. A ball is thrown straight upward with an initial velocity of 15 m/s. What is
its velocity at the highest point?
A. 15 m/s
B. 9.8 m/s
C. 0 m/s
D. −9.8 m/s
Correct Answer: C
Rationale: At the highest point, the ball momentarily stops before changing
direction.
4. An object moves with constant velocity. Which statement must be true?
A. The object has zero acceleration
B. The object has increasing momentum
C. The net force is nonzero
D. The object is at rest
Correct Answer: A
Rationale: Constant velocity means no change in velocity, so acceleration is zero.
,5. A net force of 10 N acts on a 2 kg object. What is the acceleration?
A. 5 m/s²
B. 10 m/s²
C. 20 m/s²
D. 0.2 m/s²
Correct Answer: A
Rationale: Newton’s second law gives a = F/m = = 5 m/s².
6. Which of the following best describes inertia?
A. Resistance to acceleration
B. Ability to do work
C. Rate of change of momentum
D. Gravitational attraction
Correct Answer: A
Rationale: Inertia is an object’s resistance to changes in its motion.
7. If the net force on an object is zero, the object:
A. Must be at rest
B. Must be slowing down
C. Moves with constant velocity
D. Has zero momentum
Correct Answer: C
Rationale: Zero net force implies no acceleration, so velocity remains constant.
, 8. A box slides across a rough floor at constant speed. The frictional force is 15
N. What is the magnitude of the applied force?
A. 0 N
B. 7.5 N
C. 15 N
D. 30 N
Correct Answer: C
Rationale: Constant speed means net force is zero, so applied force equals friction.
9. Which force always acts perpendicular to the direction of motion in
uniform circular motion?
A. Friction
B. Centripetal force
C. Gravitational force
D. Normal force
Correct Answer: B
Rationale: Centripetal force points toward the center of the circular path.
10. The SI unit of work is:
A. Newton
B. Watt
C. Joule
D. Kilogram
Correct Answer: C
Rationale: Work is measured in joules (N·m).