Physics mcqs on periodic motion for competitive exams preparation
ANS KEY IS AT THE END
IV. PERIODIC MOTION
1. Which law states in simple terms
that stress (force per unit area) is directly proportional to strain
(fractional deformation)?
(a) Newton’s (b) Hooke’s
(c) Kepler’s (d) Ohm’s
2. In simple harmonic motion
(SHM), we have the conservation of
(a) kinetic energy (b) potential
energy
(c) total energy (d) electrical
energy
3. The angular frequency, time period and frequency in SHM does not depend upon
(a) mass (b) force
constant
(c) amplitude (d) all of the above
4 . The angular frequency, time period and frequency of a simple pendulum depends
only on the
(a) mass and amplitude (b) mass
and acceleration (g)
(c) amplitude and mass (d)
length (L) and acceleration (g)
5. When the restoring force is
proportional to the ________ from equilibrium, the oscillation is called simple
harmonic motion (SHM)
(a) displacement (b)
velocity
(c) time (d)
frequency
6. A body that undergoes simple harmonic motion is called a harmonic
(a) oscillator (b) amplifier
(c) pendulum (d) none of the
above
7. Which of the following physical systems are examples of simple harmonic
oscillator?
(a) mass on spring (b)
mass on a pendulum
(c) uniform circular motion (d) all of the above
8. The period of pendulum is determined by its
(a) mass (b) amplitude
(c) speed (d) length
9. SHM may be assumed as a projection of uniform circular motion
along a
(a) diagonal (b) hypotenuse
(c) radius (d) diameter
10. A body experiences SHM with an amplitude. When this body is at
its maximum displacement its phase is
(a) π/4 (b) π/2
(c) π (d) 2π
11. The amplitude of a
vibrating body placed in a resisting
medium
(a) increases exponentially with time
(b) decreases exponentially
with time
(c) remain constant with time
(d) none of the above
12. Two particles are executing SHM of same period. If the second particle starts
form mean position T/2 later than the first the phase difference between the
two particles at any
instant of time is
(a) 3π/2 b) π/4
(c) π/2 d) π
13. The total energy of a body
executing SHM is directly proportional to
(a) the amplitude
(b) the square of the
amplitude
(c) square root of the amplitude
(d) reciprocal of the amplitude
14. The circular motion of a particle with constant speed is
(a) periodic and SHM (b)
periodic and SHM
(c) periodic but not SHM (d)
neither periodic nor SHM
15.
Two SHM are represented by y1 = 0.1sin (100 πt + π/3) and y2
= 0.1 cos πt. The phase difference of the velocity of 1st with respect to 2nd t=0
is
(a) π/3 (b) π/2
y1=0.1sin(100πt+π/3)
y2=0.1cosπt= 0.1sin(π/2+πt)= 0.1sin(πt+ π/2)
Now, for finding velocity of particle , differentiate
both equations with respect to time .
dy1/dt = v1=0.1×100πcos(100πt+π/3)
similarly for 2nd equation,
dy2/dt = v2 =0.1×πcos(πt+π/2)=0.1πcos(πt+π/2)
if equation x=Asin(ωt+ϕ) is given then, at t=0 phase of motion is ϕ
similarly at t=0 phase of 1st particle velocity is π/3
at t=0 phase of velocity of 2nd particle is π/2
now the phase difference = phase of 1st particle
at t=0 - phase of 2nd particle
at t=0
=π/3−π/2= −π/6
(c) -π/6 (d) π/6
16. If E is the total energy of a particle experiencing
SHM and A is the amplitude; the E and A are related as
(a)
E ∝ 1/A2 (b)
E ∝
1/A
(c) E ∝ A (d) E ∝A^2
E= ½ KA2
⇒ E ∝ A2
17. The displacement of particle in SHM in one time period is
(a) zero (b) a
(c) 2a (d) 4a
zero
In one time
period, the particle in SHM comes back to its original position. So the
displacement will be zero. But the distance traveled will be equal to 4a. So the option 'A' is correct.
18. The frequency of SHM is 100 Hz. Its time period is
(a) 0.1 s (b) 0.01 s f=1/T⇒T=1/f
⇒T=1/100=0.01s
(c) 1s (d) 100 s
19. Which of the following is not essential for the free oscillation of a mass attached
to a spring?
(a) elasticity (b) gravity
(c) inertia (d) restoring
force
20. Which of the following quantities associated with SHM do not vary periodically?
(a) velocity (b) displacement
(c) acceleration (d) total
energy
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