# Intro to Simple Pendulum

## Trending Questions

**Q.**The length of a simple pendulum is 39.2π2 m. If g=9.8 m/s2, the time period of pendulum is

- 2 s
- 8 s
- 4 s
- 3 s

**Q.**

A simple pendulum attached to the ceiling of a stationary lift has a time period T. The distance y covered by the lift moving upwards varies with time t as y=t2 where y is in metre and t in second. If g=10ms−2, the time period of the pendulum will be

√45T

√56T

√54T

√65T

**Q.**A small sphere carrying a charge ‘q’ is hanging in between two parallel plates by a string of length L. Time period of pendulum is T0. When parallel plates are charged, the time period changes to T. The ratio TT0 is equal to

- None of these
- (g+qEmg)1/2
- (gg+qEm)3/2
- (gg+qEm)1/2

**Q.**In a uniform magnetic field, the magnetic needle has a magnetic moment 9.85×10–2 A/m2 and moment of inertia 5×10–6 kg m2. If it performs 10 complete oscillations in 5 seconds then the magnitude of the magnetic field is

[Take π2 as 9.85]

**Q.**

The length of the second’s pendulum on the surface of earth is 1m. The length of second’s pendulum on the surface of moon, where g is 16th value of earth surface, is:

16m

136m

6m

36m

**Q.**Find the time period of torsional pendulum.

**Q.**

Does air resistance affect the period of a pendulum$?$

**Q.**A simple pendulum is made of a body which is a hollow sphere containing mercury, suspended by means of a wire. If a little mercury is drained off, then the time period of pendulum

- Increase
- Remains unchanged
- Decrease
- Become erratic

**Q.**

A simple pendulum makes $10$ oscillations in $20$ seconds. What is the time period and frequency of its oscillation?

**Q.**

How do you double the period of a pendulum?

**Q.**If the metal bob of a simple pendulum is replaced by a wooden bob, then its time period will

- Decrease
- Increase
- Remain the same
- May increase or decrease

**Q.**Why does the pendulum stop after oscillating for a while?

**Q.**A bob of a simple pendulum of mass 40gm with a positive charge 4×10−6 is oscillating with time period ‘T1’. An electric field of intensity 3.6×104 N/c is applied vertically upwards now time period is T2. The value of ′T′2T1 is (g = 10 m/s2)

- 0.16
- 0.64
- 1.25
- 0.8

**Q.**A pendulum clock of time period 2 sec gives the correct time at 30∘C. The pendulum is made of iron. How many seconds will it lose or gain per day when the temperature falls to 0∘C ? αFe=1.2×10−5(∘C)−1

- 15.5 sec
- 20.5 sec
- 30.5 sec
- No gain/loss.

**Q.**Magnets A and B are geometrically similar but the magnetic moment of A is twice that of B. If T1 and T2 are the time periods of oscillation when their like poles and unlike poles are kept together respectively, then T1T2 will be -

- 13
- 12
- 1√3
- √3

**Q.**

Why do shorter pendulums swing faster?

**Q.**

Length of a seconds pendulum is approximately:

9.9 cm

99.9 cm

99 cm

999 cm

**Q.**A simple pendulum with a brass bob has a time period T. The bob is now immersed in a non-viscous liquid and oscillated. If the density of the liquid is 18 that of brass, the time period of the same pendulum will be

- √87T
- 8272T
- T
- 87T

**Q.**When will the motion of a simple pendulum be simple harmonic?

**Q.**

A particle of mass $0.1kg$ executes SHM under a force $F=(-10x)N$. Speed of particle at mean position is $6m/s.$Then amplitude of oscillations is

$0.6m$

$0.2m$

$0.4m$

$0.1m$

**Q.**A simple pendulum of bob mass m is oscillating with an angular amplitude αm (in radian). The maximum tension in the string is

- mgα2m
- mg
- mgαm
- mg(1+α2m)

**Q.**The bob of simple pendulum having density 40003 kg/m3 executes SHM in water with a period ′t′ s. If the period of oscillation of bob in air is 10 s, find the value of ′t′.

(Neglect frictional force of water, take density of water as 1000 kg/m3)

- 10
- 20
- 30
- 40

**Q.**

For small oscillations, a pendulum of length L is released from rest. Its length is L and time period is T. vertically below the point of suspension O, there is an obstacle P at a vertical distance x. the pendulum returns back to its original position after time 5T8. Find x.

L/2

13L/16

15L/16

3L/4

**Q.**

In simple harmonic motion, motion is executed by a particle that is subject to a force which is ________ to the displacement of the particle and is directed toward the _________.

**Q.**Two pendulums whose lengths differ by 11 cm oscillate at the same place so that one of them makes 30 oscillations and the other 36 oscillations during same time. Find the lengths of the pendulum.

- 37 cm and 26 cm
- 25 cm and 14 cm
- 30 cm and 19 cm
- 36 cm and 25 cm

**Q.**A simple pendulum completes 40 oscillations in a minute. Find its frequency.

**Q.**A girl is swinging in a swing in a sitting position. How will the period of the swing be affected if she stands up?

**Q.**

How many vibrations, a simple pendulum will complete in 52 second?

**Q.**A thin rectangular bar magnet suspended freely has a period of oscillation of 4 s. What will be the period of oscillation if the magnet is broken into two halves (each having half the original length) and one of the pieces is made to oscillate in the same field?

- 2 s
- 4 s
- 6 s
- 8 s

**Q.**A bar magnet is free to vibrate in a horizontal plane. At the magnetic equator, the time period of oscillations is found out to be equal to T. What will be its time period of oscillations on one of the magnetic poles of earth?

- T
- T2
- 2T
- infinity