Tag: physics

Questions Related to physics

A body of mass $5  kg$ undergoes a change in speed from $20$ to $0.20  {m}/{s}$. The momentum of the body would

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

  1. Increase by $99 kg {m}/{s}$

  2. Decrease by $99 kg {m}/{s}$

  3. Increase by $101 kg {m}/{s}$

  4. Decrease by $101 kg {m}/{s}$

Show answer
Correct Option: B
Explanation:

$momentum=mass*\delta v=5kg*(20-0.20)=99kgm/s$

Hence it decreases by $99kgm/s$

A body of mass $0.1 kg$ is moving with a velocity of $15  {m}/{s}$. The momentum associated with the ball will be

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

  1. $0.5 kg {m}/{s}$

  2. $1.5 kg {m}/{s}$

  3. $2.5 kg {m}/{s}$

  4. $3.2 N s$

Show answer
Correct Option: B
Explanation:

P =mv = 0.1 x 15 $kgm/s$ = 1.5$kgm/s$

A hammer weighing $3  kg$, moving with a velocity of $10  {m}/{s}$, strikes against the head of a spike and drives it into a block of wood. If the hammer comes to rest in $0.025  s$, the impulse associated with the hammer will be

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

  1. $30 N s$

  2. $-30 N s$

  3. $15 N s$

  4. $-15 N s$

Show answer
Correct Option: B
Explanation:

Let J be the impulse associated with the hammer

then, $\dfrac{\Delta J}{\Delta t} = ma$ and a =$\dfrac{\Delta V}{\Delta t}$

Hence, j = m$\Delta V$

j= 3(0 - 10) Ns = -30 Ns

The combined effect of mass and velocity is taken into account by a physical quantity called 

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

  1. Torque

  2. Moment of force

  3. Momentum

  4. Moment of momentum

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Correct Option: C
Explanation:

P = mv

i.e it takes in account the factors of both m and v .

Momentum has the same units as that of 

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

  1. Impulse

  2. Torque

  3. Moment of momentum

  4. Couple

Show answer
Correct Option: A
Explanation:

Impulse applied to an object produces an equivalent vector change in its linear momentum, also in the same direction. The SI unit of impulse is the newton second $(N⋅s)$, and the dimensionally equivalent unit of momentum is the kilogram meter per second $(kg⋅m/s).$

Newton used the phrase 'quantity of motion' for

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

  1. Momentum

  2. Force

  3. Acceleration due to gravity

  4. None of these

Show answer
Correct Option: A
Explanation:

quantity of motion in a body, the relative amount of its motion, as measured by its momentum, varying as the product of mass and velocity.which is define as momentum.

$Mass \times velocity$ =

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

  1. Impulse

  2. Momentum

  3. Area

  4. Force

Show answer
Correct Option: B
Explanation:

Momentum of the body is defined as the product of mass of the body and its velocity.

$\therefore$     Momentum    $\vec{P} = m\vec{v}$

Momentum is a________quantity. Fill in the blank. 

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

  1. scalar

  2. vector

  3. tensor

  4. none

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Correct Option: B
Explanation:

As momentum of the body has both magnitude as well as direction, thus momentum is a vector quantity.
Momentum of the body       $\vec{P} = m\vec{v}$

Momentum measures the amount of:

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

  1. Inertia in a body

  2. Acceleration of a body

  3. Velocity of a body

  4. Motion of a body

Show answer
Correct Option: D
Explanation:

Momentum is the quantity of motion of a body which is defined as the product of mass of body and its velocity.

$\therefore$ Momentum    $P = mv$

If the momentum of a flying brick is $50\ kg\ m/s$ and its mass is $10\ kg$. Calculate its velocity?

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

  1. $500\ m/s$

  2. $2\ m/s$

  3. $5\ m/s$

  4. None

Show answer
Correct Option: C
Explanation:

Given :    $P = 50$  $kg$ $m/s$                    $m = 10$  kg

$\therefore$ Velocity of brick       $v = \dfrac{P}{m} = \dfrac{50}{10} = 5$ $m/s$