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 force and newton's laws momentum (p) introduction to momentum linear momentum

Momentum is a measure of 

  1. Weight

  2. Mass

  3. Quantity of motion

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

Momentum is mass* velocity.

For motion two questions are important, " How much is moving? " and "How fast is it moving?'
For change in state, inertia is necessary. Inertia is mass for translational motion. 
So, Quantity of motion is momentum.

Multiple choice physics force and newton's laws of motion momentum (p) introduction to momentum linear momentum

If the same force is applied on two bodies of different masses for the same time, then the change produced in the momentum of the two bodies is also same .

  1. True

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

According to Newton's second law,

F = ma = m (v - u)/ t
Ft = mv - mu = Change in momentum
Now, for two bodies, if Ft is same, change in momentum is also same.
So, given statement is true.

Multiple choice physics force and newton's laws of motion momentum (p) introduction to momentum linear momentum

Which of the following statements are correct regarding linear momentum of a body?

  1. It is a measure of quantity of motion contained by the body.

  2. Change in momentum is the measurement of impulse.

  3. Impulse and acceleration act in same direction to the change in momentum.

  4. Incase of uniform circular motion, the linear momentum is conserved.
Reveal answer Fill a bubble to check yourself
A,B Correct answer
Explanation

Momentum, P = Mv

So, it gives quantity of motion. Option A is correct.
By Newton's second law,
Ft = mv-mu, So option B is correct.
The direction of impulse can be opposite to that of change in momentum. Option C is wrong.
The Uniform circular motion is accelerated motion. So, momentum is not conserved.
Option D is wrong.
Hence, Options A and B are correct.

Multiple choice physics force and newton's laws of motion momentum (p) introduction to momentum linear momentum

Momentum is closely related to:

  1. force

  2. impulse

  3. velocity

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

Momentum of an object is due to its mass and velocity. m x v = momentum. Mass remains constant for any object. The value of momentum mostly depends on the value of velocity. Thus, velocity out of the four options is closely related to momentum.

Multiple choice physics force and newton's laws of motion momentum (p) introduction to momentum linear momentum

If the acceleration of an object is zero:

  1. it must be at rest

  2. it may or may not be at rest

  3. it must be moving

  4. it must be falling freely under gravity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

From newton's  2nd law of motion, the zero acceleration implies no external force, however, the body may have uniform velocity.

Hence the body may or may not be at rest.

Multiple choice physics force and newton's laws of motion momentum (p) introduction to momentum linear momentum

An example of a force applied in the direction of motion is:

  1. Opening a door

  2. Applying brakes suddenly to a moving car

  3. A batsman hitting a cricket ball

  4. Drawing water from a well
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

While opening the door the force applied is tangential to the motion of the door.
While applying brakes the motion is on a different axis to the force applied,
When a batsman hits a ball, both the ball and the force applied are in the same direction
While drawing water from the well the motion and the force are in different directions (mostly tangential)

Multiple choice physics force and newton's laws of motion momentum (p) introduction to momentum linear momentum

The quantity that best represents the motion of a rigid body is

  1. its mass.

  2. its speed.

  3. its velocity.

  4. its linear momentum.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Mass of a body is the quantity of inertia possessed by it, or in simpler words, it is the measure of resistance that a body can provide to change in its motion.
Speed is the measure of how fast a body is moving.
Velocity is the measure of how fast a body is moving along with its direction.
Linear momentum is the quantity which denoted the motion of body along with its direction.

Multiple choice physics force and newton's laws of motion momentum (p) introduction to momentum linear momentum

In which of the following cases the net force is not zero?

  1. A kite skillfully held stationary in the sky

  2. A ball freely falling from a height
  3. An aeroplane rising upwards at an angle of $45^{\circ}$ with the horizontal with a constant speed

  4. A cork floating on the surface of water
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

If a ball freely falling from a height the net force applied on the ball is not zero as gravity is acting on it.

Multiple choice physics force and newton's laws of motion momentum (p) introduction to momentum linear momentum

The velocity of a body of mass 20 kg increases to 400 kgm/s in 5s. If initial velocity was 10 m/s, what is the momentum before the force acts?

  1. ${200 kg. m/s ^2}$
  2. $300\ kg.m/s$
  3. $200 \ kg.m/ s$
  4. $100 \ kg. m/s$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Given :   $m =20$ kg        

Initial velocity of the body        $u  = 10$ m/s
Thus initial momentum of the body         $P _i = mu  =20\times 10 = 200$  kg.m/s