Free Newton's Laws of Motion MCQs with Answers
83 Newton's Laws of Motion MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Newton’s laws explain inertia, the relation between net force and acceleration, and action-reaction pairs. Questions involve free-body diagrams, balanced and unbalanced forces, F = ma, force as the rate of change of momentum, and identifying genuine third-law pairs, which act on different bodies.
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- A. 9.8 N
- B. 19.6 N
- C. 129.4 N
- D. 39.2 N
Explanation: For an elevator accelerating upward, the apparent weight is the normal reaction N = m(g + a).
Correct answer: 39.2 N- A. Einstein
- B. Galileo
- C. Newtons
- D. Plank
Explanation: Newton formulated the inverse-square law of gravitation, F = Gm1m2/r2, which states that gravitational force decreases with the square of…
Correct answer: Newtons- A. mg
- B. mg - ma
- C. mg + ma
- D. mg - ma
Explanation: For an elevator accelerating upward, the floor must provide extra upward force, so the apparent weight is N = m(g + a), written as mg +…
Correct answer: mg + ma- A. MLT-1
- B. MLT-2
- C. ML-1T
- D. ML-1T-2
Explanation: Newton’s second law gives F = ma, so force has dimensions M × LT^-2 = MLT^-2.
Correct answer: MLT-225. The fission chain reaction in a nuclear reactor can be controlled by introducing _______________?
- A. Iron rods
- B. Graphite rods
- C. Cadmium rods
- D. Platinum rods
Explanation: Cadmium rods absorb neutrons, so inserting them into a reactor reduces the number of neutrons available to cause further fission and…
Correct answer: Cadmium rods- A. at rest
- B. moving slowly
- C. move with high velocity
- D. move with velocity comparable to velocity of light
Explanation: Newtonian mechanics is a classical approximation and becomes inaccurate when a particle's speed is comparable to the speed of light…
Correct answer: move with velocity comparable to velocity of light- A. 1st law
- B. 2nd law
- C. 3rd law
- D. all 1st, 2nd and 3rd laws
Explanation: Newton's first law states that an object remains at rest or continues with uniform velocity unless acted on by a net external force…
Correct answer: 1st law- A. force
- B. impulse
- C. velocity
- D. both A and C
Explanation: Newton's second law states that force is the time rate of change of momentum: F = Δp/Δt, measured in newtons when momentum is in kg m/s…
Correct answer: force- A. second law of motion
- B. third law of motion
- C. first law of motion
- D. law of gravitation
Explanation: A rocket moves forward by ejecting gases backward, so the gases exert an equal and opposite thrust on the rocket according to Newton's…
Correct answer: third law of motion- A. Centripetal force
- B. Gravitational force
- C. Their inertia
- D. Centrifugal force
Explanation: Passengers tend to continue moving in a straight line when the car turns, because of their inertia.
Correct answer: Centrifugal force- A. force, displacement
- B. force, velocity
- C. force, acceleration
- D. force, momentum
Explanation: Newton's second law gives F_net = ma, so the net force and acceleration have the same direction when the force is nonzero.
Correct answer: force, acceleration- A. effect of force
- B. existence of a force
- C. existence of two forces
- D. existence of pair of forces in nature
Explanation: Newton's third law states that forces occur in equal and opposite pairs between interacting bodies.
Correct answer: existence of pair of forces in nature- A. inertia
- B. motion
- C. velocity
- D. force
Explanation: Newton's first law says that a body remains at rest or in uniform straight-line motion unless acted upon by an external unbalanced force.
Correct answer: inertia- A. volume
- B. density
- C. mass
- D. temperature
Explanation: Inertia is the resistance of an object to any change in its state of motion, and this resistance increases with mass.
Correct answer: mass- A. biology
- B. physics
- C. information technology
- D. chemistry
Explanation: Physics is called a fundamental science because its laws describe basic properties of matter, energy, space and time and support many…
Correct answer: physics- A. 1
- B. 0.5
- C. 1.3
- D. 1.67
Explanation: The area of the end of the cylinder is given by:A = (π/4)d2where d is the diameter of the cylinder.Substituting the given values, we get:A…
Correct answer: 1.67- A. MLT-2
- B. ML2T-2
- C. ML2T2
- D. ML-2T-2
Explanation: From Newton's second law, force = mass x acceleration. Mass has dimension M and acceleration has dimension LT^-2, so force has dimension…
Correct answer: MLT-2- A. Mass of the body
- B. velocity of the body
- C. tension in the string
- D. centripetal acceleration
Explanation: The centripetal force required to keep an object moving in a circular path is provided by tension in the string, directed towards the…
Correct answer: tension in the string- A. maximum
- B. zero
- C. Equal to the weight of the stone
- D. less than the weight of the stone
Explanation: At the highest point in the vertical circle, the tension in the string must provide the centripetal force needed to keep the stone in…
Correct answer: Equal to the weight of the stone- A. Follows directly from Newton's second law
- B. Is the definition of angular acceleration
- C. Is the definition of linear acceleration
- D. Is the definition of torque
Explanation: Newton's second law for rotational motion is \( \tau = I\alpha \), where \( \tau \) is the net torque, \( I \) is the rotational inertia…
Correct answer: Follows directly from Newton's second law