Free Newton's Laws of Motion MCQs with Answers

• A. Joule
• B. Watt
• C. Newton
• D. Pascal

Explanation: The SI unit of force is the newton (N), defined as the force that accelerates a one-kilogram mass at one metre per second squared.

• A. force equals mass times velocity
• B. force equals the rate of change of momentum
• C. force equals mass times distance
• D. force equals momentum times time

Explanation: The general statement is that the net force equals the rate of change of momentum, which reduces to F equal to ma only when the mass is…

• A. a net force acting on it in the direction of motion
• B. zero net force acting on it
• C. a net force acting opposite to its motion
• D. an increasing acceleration

Explanation: Uniform velocity means zero acceleration, and by Newton's second law zero acceleration requires zero net force.

• A. 0.2 m s-2
• B. 5 m s-2
• C. 16 m s-2
• D. 80 m s-2

Explanation: From F equal to ma, the acceleration is 20 divided by 4, which is 5 m s-2.

• A. act on the same body and cancel out
• B. act on different bodies and therefore never cancel
• C. are unequal in magnitude
• D. act in the same direction

Explanation: The pair is equal in magnitude and opposite in direction but acts on two different bodies, which is why they cannot cancel each other and…

• A. the acceleration produced by a force
• B. inertia, the tendency of a body to resist a change in its state of motion
• C. action and reaction pairs
• D. the conservation of energy

Explanation: A body continues at rest or in uniform motion in a straight line unless a resultant force acts, so the law defines what a force actually…

• A. 4 m per second squared
• B. 100 m per second squared
• C. 0.25 m per second squared
• D. 25 m per second squared

Explanation: From F equals ma, the acceleration is 20 divided by 5, giving 4 m per second squared in the direction of the resultant force.

• A. act on the same body and therefore cancel
• B. act on two different bodies, so they never cancel each other
• C. are unequal in magnitude
• D. act in the same direction

Explanation: Action and reaction are equal and opposite but act on different objects, which is why a book on a table is held up by the table's push…

• A. greater than their true weight
• B. less than their true weight
• C. equal to their true weight
• D. zero

Explanation: The floor must both support the weight and supply the extra upward force to accelerate the person, so the normal reaction, which is what…

• A. the area of contact only
• B. the normal force pressing them together and the nature of the surfaces
• C. the speed only, in all cases
• D. the volume of the bodies

Explanation: Limiting friction is the coefficient of friction multiplied by the normal reaction, and to a good approximation it is independent of the…

• A. Accelerated frame of reference
• B. Inertial frame of reference
• C. Non-inertial frame of reference
• D. None

Explanation: Newton's first law holds in an inertial frame, where a body with no net force remains at rest or moves with constant velocity.

• A. 12N, 5N, 20N
• B. 4N ,2N, 10N
• C. 10N, 18N
• D. 12N, 5N, 15N

Explanation: For three forces to produce equilibrium, their magnitudes must be able to form a closed triangle, so the largest force must not exceed the…

• A. Moving body
• B. Body is at rest
• C. Both have not any inertia
• D. Both have same inertia because inertia depends upon mass only

Explanation: Inertia is the resistance of a body to a change in its state of motion, and it depends on mass rather than whether the body is moving or…

• A. Velocity
• B. Direction
• C. Mass
• D. Time

Explanation: Inertia depends only on mass: a greater mass requires a greater force to produce the same change in motion.

• A. Energy
• B. Work
• C. Inertia
• D. Momentum

Explanation: Newton's first law states that an object remains at rest or in uniform straight-line motion unless an unbalanced external force acts on…

• A. Newton
• B. Pound
• C. Dyne
• D. None of these

Explanation: The CGS unit of force is the dyne, defined as 1 g cm/s². In SI units the corresponding unit is the newton (N), while the pound is used in…

• A. Newton
• B. Erg
• C. Dyne
• D. Joule

Explanation: In the CGS system, force is measured in dynes, where 1 dyne = 1 g·cm/s².

• A. Electromagnetic Force
• B. Gravitational Force
• C. Centripetal Force
• D. Nuclear Force

Explanation: The mutual force produced by the masses of two bodies is gravitational force, described by Newton's law of gravitation.

• A. More than the true weight
• B. More or less the true weight
• C. Less than the true weight
• D. Equal to the true weight

Explanation: For an upward-accelerating lift, Newton's second law gives N − mg = ma, so the apparent weight is N = m(g + a), which is greater than the…

• A. a frame of reference which is either at rest or moves with a constant velocity is called an inertial frame of reference
• B. an un-accelerated frame of reference is called an inertial frame of reference
• C. all the frames of reference in uniform rectilinear motion are equivalent
• D. Newtons laws of motion are valid in an accelerated (non inertial) frame of reference

Explanation: An inertial frame is unaccelerated, so it is either at rest or moving with constant velocity, and all uniformly moving frames are…