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 physics the essence of change forms of energy and energy conservation energy for everything forms of energy

A body $A$ is placed on a railway platform and an identical body $B$ in a moving train. Which of the following energies of $B$ are greater than those of $A$ as seen from the ground?

  1. Kinetic

  2. Total

  3. Mechanical

  4. Internal
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

Since the body B is in a moving train, it will have higher kinetic energy as compared to the body on platfrom. It is because the speed of the body $A$ is zero.

The total energy of the body $B$ will be more than body $A$ due to its state of motion and the mechanical energy of the body $B$ will be higher due to more amount of work done on it as it is moving.

The internal energy of the two identical bodies do not depend on other external factors and it remains constant for the bodies.

So, only the internal energy will not change.

Multiple choice physics universe and space heliocentric model introduction to gravitation introduction to gravity

------------ is the force of attraction between any two bodies in the universe.

  1. Gravitation

  2. Polarity

  3. Induction

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

Any two objects attract each other with a force $F _g=\dfrac{GMm}{R^2}$ where $G$ is the gravitational constant, $M$ and $m$ the masses of the two bodies and $R$ is the distance along the line joining their centre of mass

Multiple choice physics universe and space heliocentric model introduction to gravitation introduction to gravity

The gravitational force is a

  1. contact force

  2. action at a distance force

  3. non contact force

  4. both (B) and (C)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Gravitational force is a action distance force because it can interact with an object even they are not in physical contact with each other, yet they are able to exert a push or a pull despite their physical operation. Hence gravitational force is a action at a distance force.

Gravitational force is also a non contact force because non contact force is a force which acts on an object without coming in physically contact with each other which is similar to a action at a distance force.

Multiple choice physics universe and space heliocentric model introduction to gravitation introduction to gravity

The weakest forces of interaction among all classified forces are

  1. electrostatic forces

  2. gravitational forces

  3. weak nuclear forces

  4. electromagnetic forces
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Gravitational force is the weakest of all the forces because its coupling constant is small in value. Gravity cannot be felt in day to day life because of the huge universe surrounding earth. Electromagnetic force is the strongest of all  force as it deals with microscopic particles.

Multiple choice physics universe and space heliocentric model introduction to gravitation introduction to gravity

A force which produces an acceleration in a body equal to acceleration due to gravity on earth, when the body has a unit mass is called

  1. Gravitational unit of force

  2. Gravity force

  3. Both

  4. None
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Definition of gravitational unit of force: A force which produces an acceleration in a body equal to acceleration due to gravity on earth, when the body has a unit mass is called gravitational unit of force.

Multiple choice physics universe and space heliocentric model introduction to gravitation introduction to gravity
State whether true or false.
Gravitational forces can also be repulsive like that of electrostatic forces.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Gravitational force, $F=\cfrac { G{ M } _{ 1 }{ M } _{ 2 } }{ { R }^{ 2 } } $

Now the mass of the objects can not be opposite (i.e., mass cannot be negative), thus, the nature of the force cannot be repulsive like that of electrostatic force.

Multiple choice physics electric fields introduction to electrostatic force electric force charging and discharging

An inflated balloon was pressed against a wall after it has been rubbed with a piece of synthetic cloth. It was found that the balloon sticks to the wall. What force might be responsible for the attraction between the balloon and the wall?

  1. Gravitational

  2. Magnetic

  3. Electrostatic

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

Electrostatic force is the phenomenon that results from slow-moving or stationary electrical charges. Specifically, electrostatic force is the physical reaction that holds together the electromagnetic field created by subatomic particles, such as electrons and protons. In order for electrostatic forces to remain cohesive, these particles need to independently maintain both positive and negative charges and react to each other accordingly. 
When a balloon is rubbed with a cloth, the electrons from the atoms of the cloth enter the atoms of the balloon and the number of electrons in the atoms of balloon becomes more than the number of protons. Because of that, there is a negative charge in the balloon, and in the cloth the number of electrons in its atoms become less than the number of protons, so it's positively charged.
Therefore, due to this electrostatic force, the balloon sticks to the wall.

Multiple choice modelling collisions collisions momentum work, energy and power physics

Two bodies A and B of masses 5 kg and 10 kg moving in free space in opposite directions with velocity form for second and 0.5 m per second respectively undergo a head on collision the force f of their mutual interaction varies with time T according to the given graph what can you conclude from the given information

  1. Period of Di formation is 0.2 second

  2. Coefficient of restitution is 0.5

  3. Body 0.5 m per second in the original direction

  4. Body be will 1.75 M per second in the reverse direction
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice physics turning effects of forces centre of gravity forces - vectors and moments acceleration due to gravity

Stability and center of gravity of an object whose stability can be increased by

  1. lowering center of gravity and increasing area of base

  2. lowering center of gravity and decreasing area of base

  3. moving center of gravity higher and increasing areas of base

  4. moving center of gravity higher and decreasing area of base
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The position of the centre of gravity of an object affects its stability. The lower the centre of gravity is, the more stable the object. The higher it is the more likely the object is to topple over if it is pushed.
In general, increasing the size of the base (that is area) of support increases stability.

Multiple choice physics turning effects of forces centre of gravity forces - vectors and moments acceleration due to gravity

An object can have 

  1. more than one center of gravity.

  2. only one center of gravity

  3. always two center of gravity

  4. none of the above

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Centre of gravity of an object is a specific point such that the body behaves as if the entire gravitational force is acting only at that point. It is unique for an object and can't be more than 1.

Multiple choice physics turning effects of forces centre of gravity forces - vectors and moments acceleration due to gravity

The center of gravity of an object 

  1. can never exist at a point where there is no mass.

  2. can exist at a point where there is no mass.

  3. may exist or may not exist.

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Centre of gravity of an object is a specific point such that the body behaves as if the entire gravitational force is acting only at that point. It is unique for an object and can't be more than 1.

There are some objects whose centre of gravity doesn't have any matter at it. Eg: A hollow sphere and a ring have their centres of gravity at their geometric centres. 

Multiple choice physics turning effects of forces centre of gravity forces - vectors and moments acceleration due to gravity

Center of gravity is usually located where

  1. less mass is concentrated

  2. less weight is concentrated

  3. more mass is concentrated

  4. more weight is concentrated
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Centre of gravity of an object is a specific point such that the body behaves as if the entire gravitational force is acting only at that point.

Since weight means the gravitational force acting, D is the correct option.
C is not the correct option because, for very large bodies like huge mountains, it is not at the point where more mass is concentrated