Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

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

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

  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
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

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

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?

  1. I and III only

  2. I and II only

  3. I, II and III

  4. II and III only
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

All three statements are standard definitions and properties related to inertia and Newton's first law of motion.

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

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:

  1. $30^o$
  2. $60^o$
  3. $45^o$

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
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} $ 
Multiple choice physics oscillatory motion a few applications of linear shm simple pendulum example of simple harmonic motion

In a 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.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In simple harmonic motion, the average kinetic energy and the average potential energy over one complete period are equal, both being half of the total energy.

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

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:

  1. $\sqrt{2}\pi$
  2. $16\sqrt{2} \pi$
  3. $ \dfrac{32\sqrt{2}}{\pi}$
  4. $ \dfrac{4}{\pi}$
Reveal answer Fill a bubble to check yourself
C Correct answer
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

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

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 :

  1. $\dfrac{2\pi}{3}$
  2. $\dfrac{3}{2\pi}$
  3. $\dfrac{\pi}{3}$
  4. $\dfrac{3}{\pi}$
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

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 :

  1. 3.0

  2. 2.0

  3. 1.5

  4. 1.0
Reveal answer Fill a bubble to check yourself
C Correct answer
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.
Multiple choice physics oscillations a few applications of linear shm simple pendulum example of simple harmonic motion

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. $[K = mw^{2}]$.

  1. $0.02\ N/m$.
  2. $0.032\ N/m$.
  3. $0.132\ N/m$.
  4. $0.232\ N/m$.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The equation is d^2x/dt^2 + 16x = 0. Comparing this to d^2x/dt^2 + w^2x = 0, we get w^2 = 16, so w = 4 rad/s. Given mass m = 2g = 0.002 kg, the force constant K = m * w^2 = 0.002 * 16 = 0.032 N/m.