Physics · Science General

Newtonian Mechanics and Forces

1,559 Questions

Newtonian mechanics studies the motion of objects and the physical laws governing them. This hub covers friction, gravitational force, inertia, and vector quantities. Mastering these fundamental physics concepts is essential for various government competitive exams.

Laws of motionFriction and inertiaVector and scalar quantitiesGravitational accelerationArchimedes principle

Newtonian Mechanics and Forces Questions

Multiple choice

Which of the following statements is/are false? a. The force which always opposes the motion of one object over another object in contact with it is called friction. b. Friction acts on only one of the two surfaces in contact with each other. c. Friction is caused by the interlocking of irregularities in the surface of the two objects which are in contact with each other.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct option, as this is a false statement. Friction acts on both the surfaces in contact with each other.

Multiple choice

Which of the following statements is/are false? a. The frictional force exerted by a fluid is called drag force. b. Higher the speed of an object moving through a fluid, greater will be the frictional force. c. Drag force acts in a direction similar to the direction of the motion of the object.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is a false statement. Thus, this is the correct option. Drag force acts in a direction opposite to the direction of the motion of the object.

Multiple choice

Match the following:

a. Static friction 1. It is the force resisting the motion when a body rolls on a surface.
b. Sliding friction 2. It is the maximum force present between any two objects when one object just tends to move or slip over the surface of the other object.
c. Rolling friction 3. It is the frictional force present when one object moves slowly over the surface of another object.

  1. a - 2, b - 1, c - 3

  2. a - 2, b - 3, c - 1

  3. a - 3, b - 2, c - 1

  4. a - 3, b - 1, c - 2

  5. a - 1, b - 3, c - 2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is the correct option. Static friction is the maximum force present between any two objects when one object just tends to move or slip over the surface of the other object. Sliding friction is the frictional force present when one object moves slowly over the surface of another object. Rolling friction is the force resisting the motion when a body rolls on a surface.

Multiple choice

The magnitude of frictional force exerted by a fluid on an object moving through it depends upon a. speed of the object b. shape of the object c. nature or viscosity of the fluid

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. All of these
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is the correct option. The magnitude of frictional force exerted by a fluid on an object moving through it depends upon the speed of the object, shape of the object and the nature or viscosity of the fluid.

Multiple choice

Which of the following statements is/are false? a. There can be frictional force between two surfaces when there is no relative motion between the two. b. Higher the viscosity of fluid, greater will be the frictional force acting on an object moving through it. c. When objects move through fluids, they lose some of their energy in overcoming the fluid friction, decreasing their efficiency.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. None of the above
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is the correct option, as all the statements are true. 

Multiple choice

Most significant which imposes limitations in raising the high speeds is

  1. adhesion of wheels

  2. resistance due to oscillations

  3. flange resistance

  4. air or wind resistance
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Wheel-rail adhesion is the most significant limiting factor for high-speed trains. Without sufficient friction between steel wheels and steel rails, locomotives cannot transmit tractive effort effectively. This friction coefficient is typically only 0.15-0.35 on dry rail and drops further with moisture or contamination, making it the fundamental constraint on acceleration and speed.

Multiple choice

Creep is the..... movement of rails.

  1. longitudinal

  2. diagonal

  3. horizontal

  4. vertical
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Creep refers to the gradual longitudinal movement of rails in the direction of traffic. This occurs due to the impact of moving wheels, thermal expansion, and traction forces, causing rails to progressively shift over time.

Multiple choice

On curves, to counteract the effect of centrifugal force, the level of outer rail is raised above the inner rail by a certain amount. This is called

  1. track gradient

  2. track slope

  3. super elevation

  4. horizontal gradient
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Super elevation is the raising of the outer rail above the inner rail on curves to counteract centrifugal force, ensuring trains remain stable and comfortable. Track gradient (option A) refers to vertical slope, track slope (option B) is not a standard term, and horizontal gradient (option D) incorrectly combines gradient direction with super elevation.

Multiple choice

The apparent force that acts on all masses in a non-inertial frame of reference is

  1. Van der Waals forces

  2. London dispersion forces

  3. Entropic force

  4. Pseudo force
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A fictitious force, also called a pseudo force is an apparent force that acts on all masses in a non-inertial frame of reference, such as a rotating reference frame. The force F does not arise from any physical interaction but rather from the acceleration a of the non-inertial reference frame itself.

Multiple choice

Work done by the potential energy of the object, which is above the ground is not ______________.

  1. directly proportional to the height from the ground

  2. directly proportional to the mass of the object

  3. inversely proportional to the height from the ground

  4. directly proportional to the gravitational force

  5. measured in joules
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Yes, it is correct as W is directly proportional to the height not inversely proportional. W = mass x gravity x height.

Multiple choice

The force by which an object attracts other object is directly proportional to the product of their masses, is ___________________.

  1. the frictional force

  2. the gravitational force

  3. the magnetic force

  4. the thrust

  5. the pressure
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Yes, it is the gravitational force. Every object in the universe attracts other object by a force of attraction, called gravitation, which is directly proportional to the product of masses of the objects and inversely proportional to the square of distance between them.

Multiple choice

When is the work done said to be positive?

  1. If the body is displaced in the same direction of force.

  2. If the body is displaced and returns to same point.

  3. If the body is displaced in the opposite direction of force.

  4. If the body is not displaced.

  5. If the body is displaced, irrespective of the direction of force.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Yes, if the body is displaced in the same direction of force, work done is positive.