Physics · Science General

Newtonian Mechanics and Forces

1,605 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 upthrust in fluids, archimedes' principle and floatation experimental verification of archimedes' principle archimedes' principle archimedes' principle and its applications
Archimedes principle is used for

  1. Determining the force applied on the object

  2. Determining the relative density of the object

  3. Determining the gravitational constant

  4. All the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Hydrometer works on the Archimedes principle. The level at which it floats in liquid determines its relative density.
Quantitatively, $V _0dg=V _{immersed}\rho g$

$\implies $ relative density $\rho _r=\dfrac{d}{\rho}=\dfrac{V _{immersed}}{V _0}$
Multiple choice physics upthrust in fluids, archimedes' principle and floatation experimental verification of archimedes' principle archimedes' principle archimedes' principle and its applications
Fill in the blank.
It is the ______ which makes balloon to rise in air. 

  1. Upthrust

  2. Buoyant force

  3. Both A and B

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

A balloon is filled with air at high pressure which leads to uprising of it because it experiences more buoyant force or we can say upthrust as they are same in this case.

Multiple choice physics upthrust in fluids, archimedes' principle and floatation experimental verification of archimedes' principle archimedes' principle archimedes' principle and its applications
Lactometers are based on

  1. Third law of motion

  2. Kepler's law

  3. Acceleration due to gravity

  4. Archimedes principle
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Lactometer works on the Archimedes' Principle that a solid suspended in a fluid is buoyed by a force equal to the weight of the fluid displaced. If the milk sample is pure, then the lactometer floats on it and if it is adulterated or impure, then the lactometer sinks.

Multiple choice physics upthrust in fluids, archimedes' principle and floatation experimental verification of archimedes' principle archimedes' principle archimedes' principle and its applications

An iron ball is weighed in air and then in water by a spring balance

  1. Its weight in air is more than in water

  2. Its weight in water is more than in air

  3. Its weight in same both in air and water

  4. Its weight is zero in water
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

By Archimedes Principle, an object immersed(partially or fully) in a fluid experiences a loss in weight, which is given by the weight of the fluid displaced by the body.


For the given iron ball, the weight measured in air is $W _1 = (m _\textrm{ball}-\rho _\textrm{air}V _\textrm{ball})g$
Similarly, weight measured in water is $W _2 = (m _\textrm{ball}-\rho _\textrm{water}V _\textrm{ball})g$

We know that, $\rho _\textrm{water} > \rho _\textrm{air}$
Hence, $W _2 <W _1$
i.e., Weight measured in air is more than that in water.

Multiple choice physics measurements and units summary of si units fundamental quantities system of units

The strength of force is expressed by?

  1. weight

  2. mass

  3. magnitude

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

The strength of a force is expressed by its magnitude. The magnitude of a force is expressed in the SI unit of force called Newton. One Newton is the force which can make an object of one kilogram mass to move at a speed of one meter per second.

Multiple choice physics magnetic fields and electromagnetism contact and non-contact forces comparing force in magnetic, electric and gravitational fields identifying forces

Electrostatic force and gravitational force differ in which respect?

  1. Conservative force

  2. Central force

  3. Principle of superposition

  4. Dependence on the intervening medium
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In electrostatic force, the force of medium depend on charges while the force of medium due to gravity does not depend on masses. There is no concept of induced mass.

Multiple choice physics primary concept of force and energy contact and non-contact forces comparing force in magnetic, electric and gravitational fields identifying forces

Under action of which force does water flow from an open tap towards ground?

  1. Electrostatic force

  2. Magnetic force

  3. Gravitational force

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Objects tend to move downwards to the earth because of gravity of the earth. This force, exerted on the object is known as force of gravity. 

Multiple choice physics motion, force and speed contact and non-contact forces comparing force in magnetic, electric and gravitational fields identifying forces

Which of the following is the weakest force?

  1. Nuclear force

  2. Gravitational force

  3. Electromagnetic force

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Answer is B.

Gravity is a very, very weak force. In a hydrogen molecule it pulls the two protons together with a force about 36 powers of ten weaker than the electric force between them.
Therefore, on small scales (within an atom/molecule), the other forces are much stronger, but on larger scales, it seems that gravity is a far stronger force; e.g. planets are held to the sun by gravity. 
Hence, among the given options, gravitational force is the weakest.

Multiple choice physics motion, force and speed contact and non-contact forces comparing force in magnetic, electric and gravitational fields identifying forces

There are circumstances in which two objects exert forces on one another even though they are not touching. Such forces are called (Mark the most appropriate answer)

  1. non-contact forces

  2. contact forces

  3. electric forces

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

A non-contact force is a force applied to an object by another body that is not in direct contact with it. The most familiar example of a non-contact force is weight.

Multiple choice physics motion, force and speed contact and non-contact forces comparing force in magnetic, electric and gravitational fields identifying forces

Which of the following is a non contact force?

  1. muscular

  2. electrostatic attraction

  3. elastic spring force

  4. friction force
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Coulomb electrostatic force of attraction acts between the two bodies which are separated by a finite distance, hence it is non contact force since the two bodies need not to be in contact with each other whereas the rest of the forces are contact forces.

Multiple choice physics motion, force and speed contact and non-contact forces comparing force in magnetic, electric and gravitational fields identifying forces

Gravitational force acts

  1. only between the sun and the planets moving around it.

  2. only between the earth and the bodies on it.

  3. between all bodies in the universe.

  4. only between the Sun and the earth.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Answer is C.

The force of gravity is the force with which the earth, moon, or other massively large object attracts another object towards itself. Gravitational force exists between all the bodies having mass in the universe.

Multiple choice physics motion, force and speed contact and non-contact forces comparing force in magnetic, electric and gravitational fields identifying forces

When a force is exerted on an object without any contact, the force is known as ____

  1. contact force

  2. non-contact force

  3. muscular force

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

A force applied on an object without any contact it is non-contact force, Examples are magnetic force, electrostatic force etc.