Laws of Motion is a crucial topic under the Physics section of ECET 2026, especially for CSE diploma students following the C-23 curriculum. This topic appears almost every year in APECET and TSECET and is known for its conceptual clarity and scoring potential. Whether you’re aiming for a high general science score or preparing for engineering concepts ahead, mastering Newton’s Laws and motion equations is a must.
📘 Concept Notes – Laws of Motion (Newton’s Laws)
⚖️ 1. Newton’s First Law (Law of Inertia):
- “A body remains in a state of rest or uniform motion unless acted upon by an external unbalanced force.”
- Explains the concept of inertia.
- No net force → no change in motion.
🚀 2. Newton’s Second Law (F = ma):
- “The rate of change of momentum is directly proportional to the applied force and takes place in the direction of the force.”
- Formula: F = m × a
- F = Force (N)
- m = Mass (kg)
- a = Acceleration (m/s²)
🛑 3. Newton’s Third Law:
- “For every action, there is an equal and opposite reaction.”
- Action and reaction forces act on different bodies.
🧮 Other Related Concepts:
- Momentum (p) = mass × velocity
- Impulse = Force × time = Change in momentum
- Friction: Force opposing motion.
- Static friction > Kinetic friction.
- Free-body diagram (FBD): Tool to visualize forces acting on a body.
🔟 10 Most Expected MCQs – ECET 2026 [Laws of Motion]
Q1. Newton’s First Law is also known as:
A) Law of Force
B) Law of Acceleration
C) Law of Inertia
D) Law of Reaction
Q2. Which formula represents Newton’s Second Law?
A) F = m + a
B) F = m × a
C) F = a/m
D) F = m – a
Q3. Unit of force in SI system is:
A) kg
B) m/s²
C) Newton
D) Dyne
Q4. When a force is applied on a body for some time, it produces:
A) Speed
B) Momentum
C) Impulse
D) Pressure
Q5. Frictional force always acts:
A) Along the motion
B) Against the motion
C) Upward
D) Downward
Q6. Action and reaction forces:
A) Act on the same body
B) Are unequal
C) Act on different bodies
D) Cancel each other always
Q7. If mass = 5 kg and acceleration = 2 m/s², then force is:
A) 7 N
B) 10 N
C) 12 N
D) 3 N
Q8. Which of these is a contact force?
A) Magnetic Force
B) Gravitational Force
C) Friction
D) Electrostatic Force
Q9. A body at rest will remain at rest due to:
A) Inertia
B) Acceleration
C) Gravity
D) Pressure
Q10. Which law helps to calculate the net force acting on a body?
A) First Law
B) Second Law
C) Third Law
D) None of the above
✅ Answer Key Table
| Q.No | Answer |
|---|---|
| Q1 | C |
| Q2 | B |
| Q3 | C |
| Q4 | C |
| Q5 | B |
| Q6 | C |
| Q7 | B |
| Q8 | C |
| Q9 | A |
| Q10 | B |
🧠 Explanations of All Answers
- Q1 → C: Newton’s First Law describes inertia.
- Q2 → B: Newton’s Second Law is F = m × a.
- Q3 → C: Force is measured in Newton (N) in SI.
- Q4 → C: Impulse = Force × Time.
- Q5 → B: Friction acts opposite to motion.
- Q6 → C: Action-reaction forces act on different bodies.
- Q7 → B: F = 5 × 2 = 10 N.
- Q8 → C: Friction is a contact force.
- Q9 → A: Inertia keeps the object at rest.
- Q10 → B: Newton’s Second Law is used to calculate net force.
🎯 Why This Practice Matters for ECET 2026
Physics MCQs like Laws of Motion are easy to master with proper understanding. They appear regularly and are often direct formula-based, which means they can be solved in under 20 seconds. Practicing these ensures concept clarity and fast solving ability, helping you secure top marks in General Science.
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