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TNPSC physics practice questions: motion, force and energy

By the PrepMatic team · Updated 9 Oct 2026 · 3 min read

General Science is Unit I of the TNPSC General Studies paper and carries only about 5 of the 75 questions, so it is the smallest unit. That makes it a high-return area: the physics questions are short, the syllabus is school science, and a few hours on motion, force and energy are enough to answer most of them. The five questions below use the formulas and laws that the paper keeps returning to. The matching subject guide is TNPSC General Science.

What this topic covers

• Motion: speed, velocity, acceleration and the equations of motion.
• Force and laws of motion: Newton's three laws, inertia, momentum.
• Gravitation: the difference between mass and weight, and g on Earth and the Moon.
• Work, energy and power: kinetic and potential energy, units and conversions.

Sample questions

Question 1

A net force of 20 N acts on a body of mass 5 kg. Its acceleration is:

• A. 0.25 m/s²
• B. 4 m/s²
• C. 25 m/s²
• D. 100 m/s²

Question 2

Passengers in a bus lean forward when the bus brakes suddenly. This is explained by Newton's:

• A. first law
• B. second law
• C. third law
• D. law of gravitation

Question 3

An object weighs 600 N on Earth. Its weight on the Moon, where g is about one-sixth of Earth's, is about:

• A. 3,600 N
• B. 600 N
• C. 360 N
• D. 100 N

Question 4

One watt is equal to:

• A. 1 newton per second
• B. 1 newton metre
• C. 1 joule per second
• D. 1 joule second

Question 5

The kinetic energy of a 2 kg object moving at 3 m/s is:

• A. 9 J
• B. 3 J
• C. 6 J
• D. 18 J

Answers and explanations

1. B. From F = m × a, acceleration = 20 ÷ 5 = 4 m/s².
2. A. The passengers' bodies tend to stay in motion when the bus stops, which is inertia, described by Newton's first law.
3. D. Mass does not change, but weight depends on g. On the Moon the weight is about 600 ÷ 6 = 100 N. Option B is the common mistake of forgetting that g changes.
4. C. Power is work per unit time, so 1 watt is 1 joule per second. A newton metre is a joule, which is a unit of energy, not power.
5. A. KE = ½ × m × v² = ½ × 2 × 3 × 3 = 9 J. Option D, 18 J, comes from forgetting the half.

How to prepare physics for TNPSC

Concentrate on units and definitions. TNPSC physics questions rarely need more than one formula, but they often ask for the unit of a quantity or the law behind an observation. Keep the table above as a one-page sheet and add rows for pressure (pascal, force per unit area), momentum (kg m/s) and frequency (hertz).

Pair each law with a daily example, because the paper describes the situation and expects you to name the law. Passengers jerking forward is the first law, a rocket launch or a swimmer pushing off the wall is the third law, and a loaded truck needing a larger force to accelerate is the second law.

Avoid unnecessary depth. Calculus-based mechanics, vector resolution and rotational motion are beyond the school-level syllabus that the paper uses. Use the school science books for Classes 6 to 10 and solve the exercises that end each chapter.

Continue with TNPSC physics: light, sound, heat and electricity practice, and read TNPSC chemistry: atoms and elements practice for the next science block.

Take the full topic test on PrepMatic

A PrepMatic topic test gives you about 15 questions in 30 minutes on one topic, and General Science is one of the subjects you can test separately. If the free assessment shows General Studies among your weak subjects, a mock focused on your weak subjects will help you spend the right amount of time on these small units. The Basic plan is free and includes 5 topic tests.

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