Tag: force and newton's laws of motion

Quizzes (10) Questions (223)

Questions Related to force and newton's laws of motion

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

A body of mass $5   kg$ is moving with velocity $2  { ms }^{ -1 }$. Calculate its linear momentum. 

  1. $2.5$ $kg$ ${ ms }^{ -1 }$

  2. $10$ $kg$ ${ ms }^{ -1 }$

  3. $5$ $kg$ ${ ms }^{ -1 }$

  4. $20$ $kg$ ${ ms }^{ -1 }$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

We know that $ p= mv$


where $p =$ linear momentum

$m=5kg$ mass, $v =2 m/s$ velocity

$ p = 5 \times 2 = 10 kg ms^{-1}$

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

A body P has mass 2 m and velocity 5 v. Another body Q has mass 8 m and velocity 1.25 v. Find out the ratio of momentum of P and Q.

  1. 2:1

  2. 1:1

  3. 1:2

  4. 3:2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The momentum is given as $M= mv$

Where, $m= $ mass of object, 
              $v= $ velocity of object
Momentum of first object $= 2m\times 5v = 10mv$
Momentum of second object $= 8m\times 1.25v=10mv$, taking the ratio of the magnitude of momentum of Ist and IInd objects $ |p _1|:|p _2|= 1:1$
Hence, correct answer is B.

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

Momentum of a body is defined to be the product of its mass and:

  1. speed

  2. velocity

  3. acceleration

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

The momentum is given by mass times it's velocity, and it is a vector quantity with direction same as velocity. The question states momentum is mass times it's speed, which is incorrect since it gives a scalar value. Hence the statement is false and correct answer is B.

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

If a car and a truck are moving with same momentum, the velocity of car is ........... the velocity of truck.

  1. Greater than

  2. Lesser than

  3. Equal to

  4. might be lesser than
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

We know, p$=$mv and the mass of car is less than truck.
However momentum are same, that shows  velocity of car is greater than the velocity of truck.

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

State whether the given statement is true or false :

A horse continues to apply a force in order to move a cart with a constant speed.

  1. True

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

Horse walking or running on the ground is a case of static friction. The horse moves forward but with each step it stops and then has to move again. Thus, it has to apply a constant force to keep moving.

If the ground were frictionless after the push, the horse and the cart would keep moving at the same velocity and would not be able to change the direction.

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

State whether given statement is True or False.
Linear momentum is always in the direction of velocity

  1. True

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

Linear momentum is always in the direction of Velocity.
Linear momentum is a vector quantity defined as the product of an object's mass, m, and its velocity, v. Linear momentum is denoted by the letter p and is called momentum for short: Note that a body's momentum is always in the same direction as its velocity vector. .