Tag: physics

Questions Related to physics

A person sitting in an open car moving at constant velocity throws a ball vertically up into air. Where will the ball fall?

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

  1. Outside the car

  2. In the car ahead of the person

  3. In the car to the side of the person

  4. Exactly in the hand from which it was thrown up

Show answer
Correct Option: D
Explanation:

The ball has forward velocity equal to the velocity of the car even when ball is given velocity upwards.

So, the ball will cover the same distance as that by the car, and hence it will land in the hands of the person.

Who among the following anticipated Newton by declaring that all things gravitate to the earth?

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

  1. Buddhagupta

  2. Varahamihira

  3. Aeyabhatta

  4. Brahmagupta

Show answer
Correct Option: D
Explanation:

Brahmagupta  the  anticipated Newton by declaring that all things gravitate to the earth.

Hence,
option $D$ is correct answer.

Inertia is the property of a body which preserves its state of motion or uniform motion in a straight line. The following factors tell me about inertia.
I. Greater the mass of a body, greater is its inertia.
II. Greater the inertia of a body, the less will be the acceleration produced by a given force.
III. The law of inertia is the same as Newton's first law of motion. 
Which combination is true?

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

  1. I and III only

  2. I and II only

  3. I, II and III

  4. II and III only

Show answer
Correct Option: C

A block is moved from rest through a distance of 4m along a straight line path.The mass of the block is 5 kg,and the  force acting on it is 20 N.If the kinetic energy acquired by the block be 40J,at what angle to the path the force is acting:

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

  1. $30^o$

  2. $60^o$

  3. $45^o$

  4. none of the above

Show answer
Correct Option: B
Explanation:
From work Energy theorem 
$ \triangle w = \triangle KE $ 
$ F.S = K.E $
$ F.S cos\theta = KE  $
$ cos\theta = \frac{KE}{FS} $
$ cos\theta = 1/2 $
$ \theta = 60^{\circ} $ 

In a simple harmonic motion

physics oscillatory motion a few applications of linear shm simple pendulum example of simple harmonic motion

  1. the potential energy is always equal to the kinetic energy

  2. the potential energy is never equal to the kinetic energy

  3. the average potential energy in any time interval is equal to the average kinetic energy in that time interval

  4. the average potential energy in one time period is equal to the average kinetic energy in this period.

Show answer
Correct Option: D

The force which tries to bring a body back to its mean position is called :

physics oscillations a few applications of linear shm simple pendulum example of simple harmonic motion

  1. deforming force

  2. restoring force

  3. gravitational force

  4. buoyant force

Show answer
Correct Option: B
Explanation:

At the extreme position, kinetic energy is zero and we know to throw out S.H.M.

K.E+P.E = constant
So, P.E. should be maximum at the extreme position.

A particle executes $SHM$ with a time period of $16\ s$. At time $t=2\ s$, the particle crosses the mean position while at $t=4s$, its velocity is $4ms^{-1}$. The amplitude of motion in meter is:

physics oscillations a few applications of linear shm simple pendulum example of simple harmonic motion

  1. $\sqrt{2}\pi$

  2. $16\sqrt{2} \pi$

  3. $ \dfrac{32\sqrt{2}}{\pi}$

  4. $ \dfrac{4}{\pi}$

Show answer
Correct Option: C
Explanation:

Let the equation of $S.H.M$ is:-


$x=a\sin\left(\dfrac{2\pi }{T}t+\phi\right)$

when $t=2s, x=0$ and $T=16s$ So,

$0=a\sin \left(\dfrac{\pi}{4}+\phi\right)$

Or $\phi=-\dfrac{\pi}{4}$

Therefore the eqn of $S.H.M$ is:-

$x=a\sin =\left(\dfrac{2\pi}{T}t-\dfrac{\pi}{4}\right)$

Now at time $t=4s, V=4m/s$

 So
$V=d\times dt=a\times \dfrac{2\pi}{T}\cos\left(\dfrac{2\pi}{T}t-\dfrac{\pi}{4}\right)$

So, $4=a\times \dfrac{2\pi}{16}\cos\left(\dfrac{\pi}{2}-\dfrac{\pi}{4}\right)$

Or, $4=a\times \dfrac{\pi}{8}\times \dfrac{1}{\sqrt{2}}$

Or $a=\dfrac{32\sqrt{2}}{\pi}$

Hence option $C$ is correct

The particle is executing S.H.M. on a line 4 cms long. If its velocity at its mean position is 12 cm/sec, its frequency in Hertz will be :

physics oscillations a few applications of linear shm simple pendulum example of simple harmonic motion

  1. $\dfrac{2\pi}{3}$

  2. $\dfrac{3}{2\pi}$

  3. $\dfrac{\pi}{3}$

  4. $\dfrac{3}{\pi}$

Show answer
Correct Option: B
Explanation:

Given,


$A=4cm$


$v=12cm/s$ at $x=0$ mean position

The velocity of particle performing S.H.M is given by

$v=\omega \sqrt{A^2-x^2}$

$12=\omega \sqrt{4^2-0}$

$12=4\omega$

$\omega =2\pi f=3$

$f=\dfrac{3}{2\pi}$

The correct option is B.

An object is attached to the bottom of a light vertical spring and set vibrating. The maximum speed of the object is 15 ${ cms }^{ -1 }$ and the period is 628 milli-seconds. The amplitude of the motion in centimeters is :

physics oscillatory motion a few applications of linear shm simple pendulum example of simple harmonic motion

  1. 3.0

  2. 2.0

  3. 1.5

  4. 1.0

Show answer
Correct Option: C
Explanation:

Given,


$T=628ms=0.628s$


$v _{max}=15cm/s=0.15m/s$

The maximum speed of the object is given by

$v _{max}=A\omega=A\dfrac{2\pi}{T}$

Amplitude, $A=\dfrac{v _{max}T}{2\pi}$

$A=\dfrac{0.15\times 0.628}{2\times 3.14}=0.015 m$

$A=1.5cm$

The correct option is C.

The different equation for linear SHM of a partial of mass $2g$ is $\dfrac {d^{2}x}{dt^{2}} + 16x = 0$. Find the force constant. $[K = mw^{2}]$.

physics oscillations a few applications of linear shm simple pendulum example of simple harmonic motion

  1. $0.02\ N/m$.

  2. $0.032\ N/m$.

  3. $0.132\ N/m$.

  4. $0.232\ N/m$.

Show answer
Correct Option: B