Work, Energy, And Power Important Questions for NEET Physics - 2026

1. Multiple choice questions.

Q1. When a force $\vec{F}$ moves an object in its direction through a distance $s$, the work done is:

• (a) $Fs$
• (b) $F/s$
• (c) $Fs\cos\theta$
• (d) $Fs\sin\theta$

Answer: (a) $Fs$

Q2. A spring with force constant $k$ is compressed by a distance $x$. The potential energy stored in it is:

• (a) $kx$
• (b) $\frac{1}{2}kx^2$
• (c) $\frac{1}{2}k/x^2$
• (d) $kx^2$

Answer: (b) $\frac{1}{2}kx^2$

Q3. In an elastic collision between two bodies, which of the following quantities is conserved?

• (a) Kinetic energy only
• (b) Momentum only
• (c) Both kinetic energy and momentum
• (d) Neither kinetic energy nor momentum

Answer: (c) Both kinetic energy and momentum

Q4. Power is defined as:

• (a) Rate of doing work
• (b) Work done per unit area
• (c) Force per unit work
• (d) None of the above

Answer: (a) Rate of doing work

Q5. Work done by a conservative force around a closed path is:

• (a) Always positive
• (b) Always negative
• (c) Zero
• (d) Maximum

Answer: (c) Zero

2. Very Short Answer (VSA).

Q1. Define work done by a variable force.

Answer: Work done by a variable force is the integral of force over the displacement, i.e., $W = \int \vec{F} \cdot d\vec{s}$, where force may change with position.

Q2. What is the SI unit of power?

Answer: The SI unit of power is watt (W), which is equal to one joule per second.

Q3. State the work-energy theorem.

Answer: The work–energy theorem states that the net work done by all forces on a particle equals the change in its kinetic energy.

3. Short Answer Questions.

Q1. Explain the difference between conservative and non-conservative forces with examples.

Answer: Conservative forces, like gravity or spring force, have work independent of path and zero work in a closed loop. Non-conservative forces, such as friction, have work dependent on path and cause energy dissipation as heat or sound.

Q2. Describe in brief the conservation of mechanical energy for a body in free fall.

Answer: As a body falls freely under gravity, its potential energy decreases while kinetic energy increases by the same amount. The sum of kinetic and potential energies (mechanical energy) remains constant, assuming air resistance is negligible.

Q3. A spring with a force constant $200\, \rm N/m$ is compressed by $0.1$ m. Calculate the potential energy stored in the spring.

Answer:

1. Potential energy, $U = \frac{1}{2}kx^2$.
2. $k = 200\, \rm N/m$, $x = 0.1$ m.
3. $U = \frac{1}{2} \times 200 \times (0.1)^2 = 1\, \rm J$.

Q4. Two bodies of masses $m_1$ and $m_2$ undergo an elastic head-on collision. Write the equations for conservation of momentum and kinetic energy.

Answer: For momentum: $m_1u_1 + m_2u_2 = m_1v_1 + m_2v_2$. For kinetic energy: $\frac{1}{2}m_1u_1^2 + \frac{1}{2}m_2u_2^2 = \frac{1}{2}m_1v_1^2 + \frac{1}{2}m_2v_2^2$, where $u$ and $v$ are initial and final velocities.

4. True or False Questions.

Q1. In an inelastic collision, kinetic energy is always conserved.

Answer: False

Q2. The area under the force-displacement graph represents work done.

Answer: True

Q3. Power is a scalar quantity.

Answer: True

3. Fill in the Blanks Questions.

Q1. The work done by gravity when a body moves from point A to point B depends only on the _____ positions.

Answer: initial and final

Q2. The potential energy stored in a stretched spring is given by the formula ______.

Answer: $\frac{1}{2}kx^2$

Q3. In a vertical circle, the tension in the string is maximum at the ______ position.

Answer: lowest

Key Advantages of Learning Work, Energy, and Power for NEET

Understanding Work, Energy, and Power in Physics helps NEET aspirants tackle vital concepts with confidence. These questions highlight important formulas, simple numerical applications, and practical reasoning—key for quick revision before exams.

Practice from this chapter builds strong conceptual clarity on kinetic and potential energy, conservation laws, and the role of forces in daily life situations. This is crucial for NEET Physics success and deeper topic understanding.

With Vedantu’s curated questions, you can improve accuracy and speed in attempting NEET Physics. Every question aligns with the syllabus and latest requirements, making your Physics preparation easy and effective.