Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

Multiple choice force in shm oscillations oscillation and waves physics

Restoring force in the SHM is

  1. conservative

  2. nonconservative

  3. frictional

  4. centripetal
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A conservative force is a force with the property that the work done in moving a particle between two points is independent of the taken path. Restoring force $F=kx,$ is such kind of force and is conservative.

Multiple choice force in shm oscillations oscillation and waves physics

In SHM, select the wrong statement, where ${F}$ is the force, ${a}$ is the acceleration and ${v}$ is the velocity of the particle in SHM.

  1. $\overset{\rightarrow}{F}\times \overset{\rightarrow}{v}$  is a null vector

  2. $|\overset{\rightarrow}{F}\times \overset{\rightarrow}{a}|=0$ (always)

  3. $\overset{\rightarrow}{F}\times \overset{\rightarrow}{a}< {0}$

  4. $\overset{\rightarrow}{a}.\overset{\rightarrow}{x}<0$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The velocity, acceleration and thus the force are along the direction of motion in the SHM.

So the cross product of Force with velocity or acceleration is always zero.
Thus $A$ and $B$ are correct.
Also, acceleration is always in opposite direction to the displacement vector. So dot-product of acceleration and displacement is always negative. Thus $D$ is also correct.
$C$ is the wrong statement as the cross product of force and acceleration is strictly zero, because, $F=ma\Rightarrow ma\times a=0$.

Multiple choice force in shm oscillations oscillation and waves physics

A coin is placed on a horizontal platform, which undergoes horizontal simple harmonic motion about a mean position $O$.The coin does not slip on the platform. The force of friction acting on the coin is $F$.

  1. $F$ is always directed towards $O$

  2. $F$ is directed towards $O$ when the coin is moving away from $O$, and away from $O$ when the coin moves towards $O$

  3. $F=0$ when the coin and platform come to rest momentarily at the extreme position of the harmonic motion.

  4. $F$ is maximum when the coin and platform come to rest momentarily at the extreme position of the harmonic motion.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In horizontal SHM, the platform accelerates towards the mean position O. To prevent slipping, the static friction force must provide this acceleration, meaning the friction force must always be directed towards O.

Multiple choice force in shm oscillations oscillation and waves physics

A particle is in S.H.M of amplitude $ 2$ cm. At extreme position the force is $4$N. At the point mid-way between mean and extreme position, the force is :

  1. $1$ N

  2. $2$N

  3. $3$N

  4. $4$N
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Amplitude = 2 cm
Force = 4N
$F = mw^{2}A=4$
$F _{1} = mw^{2}x$

Since $F$ is directly proportional to $x$ so , at midpoint the force when the amplitude is $2 \ cm$ will be $2N$

Multiple choice force in shm oscillations oscillation and waves physics

A 1 kg mass executes SHM with an amplitude 10 cm, it takes $2\pi$ seconds to go from one end to the other end. The magnitude of the force acting on it at any end is :

  1. 0.1 N

  2. 0.2 N

  3. 0.5 N

  4. 0.05 N
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

As $  w  = \cfrac{2\pi}{T} = 1 \ rad/sec $ ;    Amplitude  $A  = 0.1 m$
magnitude of  force $ = m \times w^{2}.A$
                                  $=  0.1 N$

Multiple choice force in shm oscillations oscillation and waves physics

An elastic ball of density $d$ is released and it falls through a height $h$ before striking the surface of liquid of density $\rho(d < \rho)$. The motion of ball is:

  1. Periodic

  2. S.H.M.

  3. Circular

  4. Parabolic
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When the ball hits the liquid, it experiences a buoyant force greater than its weight (since d < rho), causing it to decelerate and eventually rise. It will oscillate between the surface and the depth, making the motion periodic, but it is not SHM because the forces are not linear with displacement.

Multiple choice force in shm oscillations oscillation and waves physics

A body of mass 1/4 kg is in S.H.M and its displacement is given by the relation $y= 0.05 sin(20t+\dfrac{\pi }{2})$ m. If $t$ is in seconds, the maximum force acting on the particle is:

  1. $5$ N

  2. $2.5$ N

  3. $10$ N

  4. $0.25$ N
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$F= m\omega^{2}A$
$\omega = 20   rad / sec$
$A =   0.05   m$
Thus
$F= \dfrac{1}{4}\times 20\times 20\times \dfrac{1}{20}$
$=5 N $

Multiple choice physics search of life outside earth space research and satellites artificial satellites space missions and artificial satellites

A satellite of mass $m$ revolving around the earth in a circular orbit of radius $2R$ has to be shifted to another circular orbit of radius $4R$. The energy required for this process will be ($M\rightarrow$ mass of earth, $R\rightarrow$ radius of the earth)

  1. $\dfrac {GMm}{8R}$

  2. $\dfrac {2GMm}{3R}$

  3. $\dfrac {GMm}{4R}$

  4. $\dfrac {GMm}{6R}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The total energy of a satellite in an orbit of radius r is E = -GMm / (2r). The energy required to move from 2R to 4R is E2 - E1 = (-GMm / 8R) - (-GMm / 4R) = (-GMm + 2GMm) / 8R = GMm / 8R.