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 pressure in liquids and gases pressure dependence on force and area concept of pressure pressure on surface

Fill in the blank.

Pressure is the force acting _________ on a unit area of object

  1. Perpendicularly

  2. Parallel

  3. Diagonally

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

Pressure is defined as force per unit area. The standard unit for pressure is the Pascal, which is a Newton per square meter.

$P=\dfrac{F}{A}$

Here the force acts perpendicularly on the area. 

Multiple choice physics pressure in liquids and gases pressure dependence on force and area concept of pressure pressure on surface

Effect of a force depends on the

  1. Volume of the object on which the force acts

  2. Area of the object on which the force acts

  3. Displacement caused by the force

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

Pressure is a measure of effect of force on an object.

Pressure is defined as force per unit area, that is,
$P=\dfrac{F}{A}$
Hence the effect of force depends upon the area upon which it acts. Smaller area would have greater effect for equal amount of applied force.

Multiple choice physics friction advantages and disadvantages of friction merits and demerits of friction and methods to reduce it friction: a necessary evil

Friction should always be avoided.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The given statement is false.
Friction is a necessary evil because without friction we will not be able to set our bodies in motion or stop the bodies which are in motion. Friction is absolutely necessary in our day to day activities. For eg it is the friction on the ground that helps us to walk and without friction it would not have veen possible to write on a paper.
Hence friction is important and cannot be avoided.
Multiple choice physics friction advantages and disadvantages of friction merits and demerits of friction and methods to reduce it friction: a necessary evil

A coin flicked across a table will stop, because :

  1. It is heavy

  2. No force is acting on it

  3. Earth attracts the coin

  4. Table exerts a frictional force
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

According to the first law of motion a body will remain in the state of rest or of uniform motion until or unless compelled by an external force.

In this case the coin will stop because an external force is exerted in the form of frictional force by the table that opposes the motion of the flicked coin.

Hence, correct answer is option $D$

Multiple choice physics turning effects of forces stability and centre of mass center of mass centre of mass

The centre of a mass of a rigid body lies

  1. inside the body

  2. outside the body
  3. neither $(a)$ nor $(b)$
  4. either $(a)$ or $(b)$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Centre of mass of rigid bodies may lie either inside or outside the body.

For example:  COM of solid sphere lies inside it whereas COM of uniform circular ring lies at its geometric centre where there is actually no matter.

Multiple choice physics turning effects of forces stability and centre of mass center of mass centre of mass

The centre of mass of a rigid body always lies inside the body. Is this statement true or false?

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
No it's not necessary that the centre of mass of a body should lie inside the body. Consider a circular ring, its centre of mass lies at the center of the ring where there is no content of the body. So it can also lie outside the body .
Multiple choice physics turning effects of forces stability and centre of mass center of mass centre of mass

A point at which a whole weight of body act vertically downward is ________.

  1. centre of gravity

  2. centre of mass

  3. centre of force

  4. centre of acceleration
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The center of gravity is the point where the total gravitational force (weight) of a body is considered to act. While often coincident with the center of mass, the definition specifically refers to weight.