Tag: momentum and newton's laws

Questions Related to momentum and newton's laws

State whether true or false.
Newton's first law of motion gives the concept of momentum.

physics force and newton's laws of motion first law of motion newton's first law of motion momentum and newton's laws

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

No the given statement is false at newton first law of motion gives the concept of inertia while the concept of momentum was given by second law.

State whether true or false.
A ball thrown upwards in a train moving with uniform velocity returns to the thrower. 
physics force and newton's laws of motion first law of motion newton's first law of motion momentum and newton's laws

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Since train is moving with uniform velocity so when the thrower throws the ball upward ball has already acquire the same velocity as that of moving train and have moved the same distance as that of thrower. 

When a bus suddenly takes a turn, the passengers are thrown outwards because of 

physics force and newton's laws of motion first law of motion newton's first law of motion momentum and newton's laws

  1. Inertia of motion

  2. Acceleration of motion

  3. Speed of motion

  4. Both (b) and (c)

Show answer
Correct Option: A
Explanation:

According to law of inertia of motion a body will continue moving with constant velocity until unless any force is acting on it. When a bus is moving straight the passengers inside are also moving straight but when suddenly bus turn left passengers still continue to move straight  because no force is acting on passengers so they will move with same magnitude and direction i.e. outwards when bus turns .

Which Newton's law of motion defines force?

physics force and newton's laws of motion first law of motion newton's first law of motion momentum and newton's laws

  1. First

  2. Second

  3. Third

  4. None

Show answer
Correct Option: A
Explanation:

Newton's first law of motion gives definition of force.

Newtons law are not valid in

physics force and newton's laws of motion first law of motion newton's first law of motion momentum and newton's laws

  1. Both inertial as well as non- inertial frame of reference.

  2. A frame moving with constant velocity w.r.t. an inertial frame.

  3. All reference frames which are at rest w.r.t. an inertial frame.

  4. The reference frame attached to the earth.

Show answer
Correct Option: A
Explanation:

Newton's Law is only valid in inertial frame of reference. If there is a non - inertial frame of reference then it won't be valid. 

Hence option $\textbf A$ is the correct answer.

A force vector applied on a mass is represented by $\vec {F} = 6\hat {i} - 8\hat {j} + 10\hat {k}$ and accelerates with $1\ m/s^{2}$. What is the mass of the body?

physics force and newton's laws of motion first law of motion newton's first law of motion momentum and newton's laws

  1. $14\ kg$

  2. $10\sqrt {2}kg$

  3. $2\sqrt {10}kg$

  4. $20\ kg$

Show answer
Correct Option: A
Explanation:
To find mass of the body we will use magnitude of force formula $,$ 
According to question$:-$
$\overrightarrow { F } =6-8\widehat { j } +10\widehat { k } $
Magnitude of Force $=\sqrt {\left( {{6^2} + {8^2} + {{10}^2}} \right)} $
                                  $= 14.14 N$
$m = F / a$
     $= 14.14 N / 1 m/s^2$
     $= 14.14 kg$
Hence,
option $(A)$ is correct answer.

A force is not required to keep a body in a 

physics force and newton's laws of motion first law of motion newton's first law of motion momentum and newton's laws

  1. Uniform circular motion

  2. Simple harmonic motion

  3. Motion with constant acceleration

  4. Motion with constant velocity

Show answer
Correct Option: D
Explanation:

If force on any body is zero than its acceleration should be zero that means its velocity would remain constant.

Which of the following is different from others?

physics force and newton's laws of motion first law of motion newton's first law of motion momentum and newton's laws

  1. watt-sec

  2. coulomb-volt

  3. newton-metre

  4. coulomb-frarad

Show answer
Correct Option: D

A rain drop of mass $0.1g$ is falling with uniform speed of $10{ cm/s }$. What is the net force the drop?

physics force and newton's laws of motion first law of motion newton's first law of motion momentum and newton's laws

  1. ${ 10 }^{ -2 }N$

  2. ${ 10 }^{ -3 }N$

  3. $2\times { 10 }^{ -3 }N$

  4. $zero$

Show answer
Correct Option: D
Explanation:

Uniform speed means that a body is traveling at a constant speed along a straight line. So it has no acceleration. Thus net weight $=ma=0$.

A car driver going at a speed v suddenly find a wide wall at a distance. (coefficient of friction is $\mu $) 

physics force and newton's laws of motion first law of motion newton's first law of motion momentum and newton's laws

  1. If the apply breaks, he will come to rest after a distance $\dfrac { { { v }^{ 2 } } }{ 2\mu g } $

  2. If he turn the cart in a circle to avoid hitting, then radius of the circle is $\dfrac { { { v }^{ 2 } } }{ \mu g } $

  3. It is better to apply breaks rather than to turn the vehicle in a circle

  4. It is better to turn the vehicle in a circle than to apply brakes

Show answer
Correct Option: B
Explanation:

If he turn the cart in a circle to avoid hitting then radius of the circle is $\dfrac{{{v^2}}}{{2\mu g}}$
Option $B$ is correct answer.