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Laws of Motion (Std 11) — MH-CET Physics MCQs with Solutions
Free MH-CET Physics Laws of Motion (Std 11) MCQs with step-by-step solutions covering Newton's Laws of Motion, Momentum & Impulse, Conservation of Momentum & Collisions, Friction, Connected Bodies & Pulleys, Equilibrium of Forces. Practise online on Prepizo — no login needed.
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Sample questions with solutions
Q1 — Newton's Laws of Motion · easy · theory
Newton's first law of motion states that a body continues in its state of rest or uniform motion unless:
A. Its mass changes
B. It is observed from a moving frame
C. It is acted upon by an unbalanced external force ✓ Correct
D. Friction is absent
Solution: This law defines inertia and identifies what a force actually does.
Q2 — Newton's Laws of Motion · easy · theory
The property of a body by which it resists a change in its state of rest or motion is called:
A. Inertia ✓ Correct
B. Force
C. Impulse
D. Momentum
Solution: Mass is the quantitative measure of inertia.
Q3 — Newton's Laws of Motion · easy · theory
Newton's second law of motion states that:
A. A body at rest stays at rest
B. Every action has an equal and opposite reaction
C. Momentum is always conserved
D. The rate of change of momentum equals the applied force ✓ Correct
Solution: For constant mass this reduces to the familiar $F = ma$.
Q4 — Newton's Laws of Motion · easy · theory
The mass of a body is a measure of its:
A. Momentum
B. Weight
C. Inertia ✓ Correct
D. Volume
Solution: A larger mass requires a larger force to produce the same acceleration.
Q5 — Newton's Laws of Motion · easy · numerical
A force acts on a body of mass $5\text{ kg}$ producing an acceleration of $2\text{ m/s}^2$. The force is:
A. $20\text{ N}$
B. $2.5\text{ N}$
C. $7\text{ N}$
D. $10\text{ N}$ ✓ Correct
Solution: $F = ma = 5 \times 2 = 10\text{ N}$.
Q6 — Newton's Laws of Motion · easy · numerical
A force of $10\text{ N}$ acts on a body of mass $2\text{ kg}$. Its acceleration is:
A. $0.2\text{ m/s}^2$
B. $20\text{ m/s}^2$
C. $12\text{ m/s}^2$
D. $5\text{ m/s}^2$ ✓ Correct
Solution: $a = \dfrac{F}{m} = \dfrac{10}{2} = 5\text{ m/s}^2$.
Q7 — Newton's Laws of Motion · easy · numerical
A force of $20\text{ N}$ acts on a body of mass $5\text{ kg}$. Its acceleration is:
A. $0.25\text{ m/s}^2$
B. $25\text{ m/s}^2$
C. $100\text{ m/s}^2$
D. $4\text{ m/s}^2$ ✓ Correct
Solution: $a = \dfrac{20}{5} = 4\text{ m/s}^2$.
Q8 — Newton's Laws of Motion · easy · numerical
The weight of a body of mass $10\text{ kg}$ is ($g = 10\text{ m/s}^2$):
A. $1000\text{ N}$
B. $100\text{ N}$ ✓ Correct
C. $10\text{ N}$
D. $1\text{ N}$
Solution: $W = mg = 10 \times 10 = 100\text{ N}$.
Q9 — Newton's Laws of Motion · easy · numerical
A force of $100\text{ N}$ acts on a body of mass $20\text{ kg}$. Its acceleration is:
A. $2000\text{ m/s}^2$
B. $0.2\text{ m/s}^2$
C. $20\text{ m/s}^2$
D. $5\text{ m/s}^2$ ✓ Correct
Solution: $a = \dfrac{100}{20} = 5\text{ m/s}^2$.
Q10 — Newton's Laws of Motion · easy · numerical
The net force on a body moving with constant velocity is:
A. Equal to its weight
B. Zero ✓ Correct
C. Equal to $mv$
D. Directed along its motion
Solution: Constant velocity means zero acceleration, and $F = ma = 0$.
Q11 — Newton's Laws of Motion · easy · numerical
A force produces an acceleration of $20\text{ m/s}^2$ in a body of mass $0.5\text{ kg}$. The force is:
A. $20\text{ N}$
B. $40\text{ N}$
C. $0.025\text{ N}$
D. $10\text{ N}$ ✓ Correct
Solution: $F = 0.5 \times 20 = 10\text{ N}$.
Q12 — Momentum & Impulse · easy · theory
The linear momentum of a body is defined as:
A. The product of its mass and velocity, a vector quantity ✓ Correct
B. The product of its mass and speed, a scalar quantity
C. The product of its mass and acceleration
D. The rate of change of its velocity
Solution: It points in the same direction as the velocity.
Q13 — Momentum & Impulse · easy · theory
The SI unit of linear momentum is:
A. $\text{kg}\cdot\text{m/s}^2$
B. $\text{kg}\cdot\text{m/s}$ ✓ Correct
C. $\text{kg}\cdot\text{m}^2/\text{s}$
D. $\text{N}\cdot\text{m}$
Solution: It is equivalent to the newton second, the unit of impulse.
Q14 — Momentum & Impulse · easy · theory
Impulse is defined as:
A. The product of mass and acceleration
B. The product of force and displacement
C. The rate of change of force
D. The product of force and the time for which it acts ✓ Correct
Solution: For a variable force it is the integral $\int F\,dt$.
Q15 — Momentum & Impulse · easy · theory
The SI unit of impulse is:
A. $\text{J}$
B. $\text{N}\cdot\text{s}$ ✓ Correct
C. $\text{N}\cdot\text{m}$
D. $\text{N}/\text{s}$
Solution: This is dimensionally the same as $\text{kg}\cdot\text{m/s}$, the unit of momentum.
Q16 — Momentum & Impulse · easy · numerical
A body of mass $2\text{ kg}$ moves at $5\text{ m/s}$. Its momentum is:
A. $7\text{ kg}\cdot\text{m/s}$
B. $2.5\text{ kg}\cdot\text{m/s}$
C. $10\text{ kg}\cdot\text{m/s}$ ✓ Correct
D. $25\text{ kg}\cdot\text{m/s}$
Solution: $p = mv = 2 \times 5 = 10\text{ kg}\cdot\text{m/s}$.
Q17 — Momentum & Impulse · easy · numerical
A force of $20\text{ N}$ acts for $3\text{ s}$. The impulse delivered is:
A. $180\text{ N}\cdot\text{s}$
B. $6.67\text{ N}\cdot\text{s}$
C. $60\text{ N}\cdot\text{s}$ ✓ Correct
D. $23\text{ N}\cdot\text{s}$
Solution: $J = F\Delta t = 20 \times 3 = 60\text{ N}\cdot\text{s}$.
Q18 — Momentum & Impulse · easy · numerical
A body of mass $5\text{ kg}$ has its velocity changed by $4\text{ m/s}$. The change in its momentum is:
A. $0.8\text{ kg}\cdot\text{m/s}$
B. $20\text{ kg}\cdot\text{m/s}$ ✓ Correct
C. $1.25\text{ kg}\cdot\text{m/s}$
D. $9\text{ kg}\cdot\text{m/s}$
Solution: $\Delta p = m\Delta v = 5 \times 4 = 20\text{ kg}\cdot\text{m/s}$.
Q19 — Momentum & Impulse · easy · numerical
A momentum change of $10\text{ kg}\cdot\text{m/s}$ occurs in $2\text{ s}$. The average force is:
A. $5\text{ N}$ ✓ Correct
B. $12\text{ N}$
C. $0.2\text{ N}$
D. $20\text{ N}$
Solution: $F = \dfrac{\Delta p}{\Delta t} = \dfrac{10}{2} = 5\text{ N}$.
Q20 — Momentum & Impulse · easy · numerical
A body of mass $0.1\text{ kg}$ moves at $20\text{ m/s}$. Its momentum is:
A. $20.1\text{ kg}\cdot\text{m/s}$
B. $2\text{ kg}\cdot\text{m/s}$ ✓ Correct
C. $0.005\text{ kg}\cdot\text{m/s}$
D. $200\text{ kg}\cdot\text{m/s}$
Solution: $p = 0.1 \times 20 = 2\text{ kg}\cdot\text{m/s}$.
Q21 — Conservation of Momentum & Collisions · easy · theory
The law of conservation of linear momentum holds when:
A. The kinetic energy is conserved
B. The internal forces are zero
C. The bodies are of equal mass
D. The net external force on the system is zero ✓ Correct
Solution: Internal forces cancel in pairs by the third law, so only external forces matter.
Q22 — Conservation of Momentum & Collisions · easy · theory
The recoil of a gun when a bullet is fired is a consequence of:
A. Conservation of kinetic energy
B. Newton's first law
C. Conservation of linear momentum ✓ Correct
D. Conservation of mass
Solution: The total momentum before firing is zero, so the gun and bullet must carry equal and opposite momenta.
Q23 — Conservation of Momentum & Collisions · easy · theory
In a perfectly elastic collision:
A. Only momentum is conserved
B. Only kinetic energy is conserved
C. Neither is conserved
D. Both momentum and kinetic energy are conserved ✓ Correct
Solution: Real collisions between macroscopic bodies are never perfectly elastic.
Q24 — Conservation of Momentum & Collisions · easy · theory
In an inelastic collision:
A. Momentum is conserved but kinetic energy is not ✓ Correct
B. Neither is conserved
C. Kinetic energy is conserved but momentum is not
D. Both are conserved
Solution: The lost kinetic energy appears as heat, sound and deformation.
Q25 — Conservation of Momentum & Collisions · easy · numerical
The coefficient of restitution for a perfectly elastic collision is:
A. Infinite
B. $0$
C. $1$ ✓ Correct
D. $0.5$
Solution: The relative speed of separation equals that of approach.
Q26 — Conservation of Momentum & Collisions · easy · numerical
The coefficient of restitution for a perfectly inelastic collision is:
A. $1$
B. $0.5$
C. $0$ ✓ Correct
D. Infinite
Solution: The bodies move together, so the relative velocity of separation is zero.
Q27 — Friction · easy · theory
Static friction is the frictional force that acts:
A. Only on rolling bodies
B. Between surfaces in relative motion
C. Only in the absence of an applied force
D. Between surfaces at rest relative to each other ✓ Correct
Solution: It adjusts itself up to a maximum value called limiting friction.
Q28 — Friction · easy · theory
Friction always acts in a direction that:
A. Is perpendicular to the surfaces
B. Assists the applied force
C. Is vertically downward
D. Opposes the relative motion or the tendency to relative motion ✓ Correct
Solution: It is a self-adjusting force in the static case.
Q29 — Friction · easy · theory
Of sliding, static and rolling friction, the smallest for given surfaces is:
A. Static friction
B. They are all equal
C. Sliding friction
D. Rolling friction ✓ Correct
Solution: This is why wheels and ball bearings are used to reduce resistance to motion.
Q30 — Connected Bodies & Pulleys · easy · theory
The tension throughout a light inextensible string passing over a smooth pulley is:
A. Greater near the heavier mass
B. Zero
C. Greater near the lighter mass
D. The same everywhere ✓ Correct
Solution: A massless string and frictionless pulley cannot support any difference in tension.