Physics · Science General

Collisions, Momentum and Kinetic Energy

385 Questions

Collisions, momentum, and kinetic energy questions analyze the principles of elastic and inelastic impacts. They require calculating mass, velocity, and conserved energy during physical interactions. These foundational physics topics are essential for most government engineering and general science examinations.

Elastic collisionsInelastic collisionsMomentum calculationKinetic energy principlesVelocity after impact

Collisions, Momentum and Kinetic Energy Questions

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

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

A metallic ball strikes a wall and falls down whereas a tennis ball having the same mass and velocity bounces back. The conclusion from this is that :

  1. Both suffer equal change in momentum

  2. The tennis ball suffers a greater change in momentum

  3. Metallic ball suffers a greater change in momentum

  4. The momentum of the tennis ball is less than that of the metallic ball
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For metallic ball,

$ \triangle P _M =0-mu=-mu$
For tennis ball,
$ \triangle P _T= -mu-mu = -2mu$
$ \therefore Option\ B\ is\ correct.$ 

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

A ball comes back after an elastic collision with a wall, If initial momentum of the ball is P, the impulse on the wall after the collision is :

  1. $P$
  2. $2P$
  3. $zero$
  4. $-2P$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Initial momentum of the ball $=P$

 Final momentum of the ball $=-P$ 
Change in momentum $=-2P$
Impulse on the wall is equal to the change in momentum imparted on the wall $=2P$

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

Choose the wrong statement

  1. $1 kg \ wt = 9.8 N$

  2. Momentum is a vector quantity

  3. Force is always conserved

  4. Momentum is conserved in the absence of an external force
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Forces that do not store energy are called nonconservative or dissipative forces. Friction is a nonconservative force, and there are others. Any friction-type force, like air resistance, is a nonconservative force.

Force is always conserved is the wrong statement.

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

A stone attains a momentum of $1\ kg\ m/s$ when it flies with a velocity of $2\ m/s$, then what will be the mass of the stone?

  1. $500\ g$
  2. $2\ kg$
  3. $2\ g$

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

Given :    $P = 1$ $kg$ $m/s$                  $v =2$ m/s

Momentum of the stone        $P = mv$
$\therefore$  Mass of stone     $m = \dfrac{P}{v} =\dfrac{1}{2} = 0.5$ kg  $=500$ g

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

The mass of a goods lorry is $4000\ kg$ and the mass of goods loaded on it is $20000\ kg$. If the lorry is moving with a velocity of $2\ m/s$ what will be its momentum?

  1. $48000\ kg\ m/s$
  2. $48\ kg\ m/s$
  3. $4.8\ kg\ m/s$

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

Given :    $m _1 = 4000$ kg           $m _2  =20000$ kg             $v =2$ m/s

Total mass of the 'lorry + goods' system      $M = 4000+20000 =24000$ kg
$\therefore$ Total momentum of the system        $P = Mv = 24000\times 2 =48000$  $kg$ $m/s$