# Quiz 14: Oscillations

Physics & Astronomy

Q 1Q 1

The position x of an object varies with time t. For which of the following equations relating x and t is the motion of the object simple harmonic motion? (There may be more than one correct choice.)
A) x = 5 sin

^{2}3t B) x = 8 cos 3t C) x = 4 tan 2t D) x = 5 sin 3t E) x = 2 cos(3t - 1)Free

Multiple Choice

B, D, E

Q 2Q 2

A restoring force of magnitude F acts on a system with a displacement of magnitude x. In which of the following cases will the system undergo simple harmonic motion?
A) F
B) F sin x
C) F x

^{2}D) F x E) F 1/xFree

Multiple Choice

D

Q 3Q 3

An object is executing simple harmonic motion. What is true about the acceleration of this object? (There may be more than one correct choice.)
A) The acceleration is a maximum when the displacement of the object is a maximum.
B) The acceleration is a maximum when the speed of the object is a maximum.
C) The acceleration is a maximum when the displacement of the object is zero.
D) The acceleration is zero when the speed of the object is a maximum.
E) The acceleration is a maximum when the object is instantaneously at rest.

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Multiple Choice

A, D, E

Q 4Q 4

The simple harmonic motion of an object is described by the graph shown in the figure. What is the equation for the position x(t) of the object as a function of time t?
A) x(t) = (4.0 m)sin[(2π/8.0 s)t + π/3.0]
B) x(t) = (4.0 m)cos[(2π/8.0 s)t + 2π/3.0]
C) x(t) = (4.0 m)cos[(2π/8.0 s)t + π/3.0]
D) x(t) = (4.0 m)cos[(2π/8.0 s)t - π/3.0]
E) x(t) = (8.0 m)cos[(2π/8.0 s)t + π/3.0]

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Multiple Choice

Q 5Q 5

Which of following graphs describes simple periodic motion with amplitude 2.00 cm and angular frequency 2.00 rad/s?
A)
B)
C)
D)
E)

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Multiple Choice

Q 6Q 6

A mass M is attached to an ideal massless spring. When this system is set in motion with amplitude A, it has a period T. What is the period if the amplitude of the motion is increased to 2A?
A) 2T
B) T/2
C) T
D) 4T
E) T

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Multiple Choice

Q 7Q 7

A mass M is attached to an ideal massless spring. When this system is set in motion, it has a period T. What is the period if the mass is doubled to 2M?
A) 2T
B) T/2
C) T
D) 4T
E) T

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Multiple Choice

Q 8Q 8

In simple harmonic motion, the speed is greatest at that point in the cycle when
A) the magnitude of the acceleration is a maximum.
B) the displacement is a maximum.
C) the magnitude of the acceleration is a minimum.
D) the potential energy is a maximum.
E) the kinetic energy is a minimum.

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Multiple Choice

Q 9Q 9

If we double only the amplitude of a vibrating ideal mass-and-spring system, the mechanical energy of the system
A) increases by a factor of .
B) increases by a factor of 2.
C) increases by a factor of 3.
D) increases by a factor of 4.
E) does not change.

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Multiple Choice

Q 10Q 10

If we double only the mass of a vibrating ideal mass-and-spring system, the mechanical energy of the system
A) increases by a factor of .
B) increases by a factor of 2.
C) increases by a factor of 3.
D) increases by a factor of 4.
E) does not change.

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Multiple Choice

Q 11Q 11

If we double only the spring constant of a vibrating ideal mass-and-spring system, the mechanical energy of the system
A) increases by a factor of .
B) increases by a factor of 2.
C) increases by a factor of 3.
D) increases by a factor of 4.
E) does not change.

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Multiple Choice

Q 12Q 12

An object is attached to a vertical ideal massless spring and bobs up and down between the two extreme points A and B. When the kinetic energy of the object is a minimum, the object is located
A) at either A or B.
B) midway between A and B.
C) 1/3 of the distance from A to B.
D) 1/4 of the distance from A to B.
E) 1/ times the distance from A to B.

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Multiple Choice

Q 13Q 13

A frictionless pendulum released from 65 degrees with the vertical will vibrate with the same frequency as if it were released from 5 degrees with the vertical because the period is independent of the amplitude and mass.

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True False

Q 14Q 14

A certain frictionless simple pendulum having a length L and mass M swings with period T. If both L and M are doubled, what is the new period?
A) 4T
B) 2T
C) T
D) T
E) T/4

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Multiple Choice

Q 15Q 15

A frictionless pendulum clock on the surface of the earth has a period of 1.00 s. On a distant planet, the length of the pendulum must be shortened slightly to have a period of 1.00 s. What is true about the acceleration due to gravity on the distant planet?
A) The gravitational acceleration on the planet is slightly greater than g.
B) The gravitational acceleration on the planet is slightly less than g.
C) The gravitational acceleration on the planet is equal to g.
D) We cannot tell because we do not know the mass of the pendulum.

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Multiple Choice

Q 16Q 16

In designing buildings to be erected in an area prone to earthquakes, what relationship should the designer try to achieve between the natural frequency of the building and the typical earthquake frequencies?
A) The natural frequency of the building should be exactly the same as typical earthquake frequencies.
B) The natural frequency of the building should be very different from typical earthquake frequencies.
C) The natural frequency of the building should be almost the same as typical earthquake frequencies but slightly higher.
D) The natural frequency of the building should be almost the same as typical earthquake frequencies but slightly lower.

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Multiple Choice

Q 17Q 17

A sewing machine needle moves up and down in simple harmonic motion with an amplitude of 1.27 cm and a frequency of 2.55 Hz.
(a) What is the maximum speed of the needle?
(b) What is the maximum acceleration of the needle?

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Q 18Q 18

An object is undergoing simple harmonic motion with frequency f = 9.7 Hz and an amplitude of 0.12 m. At t = 0.00 s the object is at x = 0.00 m. How long does it take the object to go from x = 0.00 m to

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Short Answer

Q 19Q 19

A simple harmonic oscillator has an amplitude of 3.50 cm and a maximum speed of 26.0 cm/s. What is its speed when the displacement is 1.75 cm?
A) 12.0 cm/s
B) 22.5 cm/s
C) 14.2 cm/s
D) 15.0 cm/s
E) 17.0 cm/s

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Multiple Choice

Q 20Q 20

The position of an object that is oscillating on an ideal spring is given by the equation x = (12.3 cm) cos[(1.26s

^{-1})t]. At time t = 0.815 s, (a) how fast is the object moving? (b) what is the magnitude of the acceleration of the object?Free

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Q 21Q 21

A machine part is vibrating along the x-axis in simple harmonic motion with a period of 0.27 s and a range (from the maximum in one direction to the maximum in the other) of 3.0 cm. At time t = 0 it is at its central position and moving in the +x direction. What is its position when t = 55 s?
A) x = -0.43 cm
B) x = -0.51 cm
C) x = +0.51 cm
D) x = -1.3 cm
E) x = -1.4 cm

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Multiple Choice

Q 22Q 22

The x component of the velocity of an object vibrating along the x-axis obeys the equation v

_{x}(t) = (0.445 m/s) sin[(25.4 rad/s)t + 0.223]. (a) What is the amplitude of the motion of this object? (b) What is the maximum acceleration of the vibrating object?Free

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Q 23Q 23

A 12.0-N object is oscillating in simple harmonic motion at the end of an ideal vertical spring. Its vertical position y as a function of time t is given by y(t) = 4.50 cm cos[(19.5 s

^{-1})t - π/8]. (a) What is the spring constant of the spring? (b) What is the maximum acceleration of the object? (c) What is the maximum speed that the object reaches? (d) How long does it take the object to go from its highest point to its lowest point?Free

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Q 24Q 24

An object of mass 8.0 kg is attached to an ideal massless spring and allowed to hang in the Earth's gravitational field. The spring stretches 3.6 cm before it reaches its equilibrium position. If this system is allowed to oscillate, what will be its frequency?
A) 2.6 Hz
B) 0.0045 Hz
C) 0.67 Hz
D) 2.1 Hz

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Multiple Choice

Q 25Q 25

An object that weighs 2.450 N is attached to an ideal massless spring and undergoes simple harmonic oscillations with a period of 0.640 s. What is the spring constant of the spring?
A) 2.45 N/m
B) 12.1 N/m
C) 24.1 N/m
D) 0.102 N/m
E) 0.610 N/m

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Multiple Choice

Q 26Q 26

A 2.25-kg object is attached to a horizontal an ideal massless spring on a frictionless table. What should be the spring constant of this spring so that the maximum acceleration of the object will be g when it oscillates with amplitude of 4.50 cm?

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Short Answer

Q 27Q 27

A 56 kg bungee jumper jumps off a bridge and undergoes simple harmonic motion. If the period of oscillation is 11.2 s, what is the spring constant of the bungee cord, assuming it has negligible mass compared to that of the jumper?
A) 17.6 N/m
B) 21.1 N/m
C) 28.2 N/m

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Multiple Choice

Q 28Q 28

A 2.0 kg block on a frictionless table is connected to two ideal massless springs with spring constants k

_{1}and k_{2}whose opposite ends are fixed to walls, as shown in the figure. What is angular frequency of the oscillation if k_{1}= 7.6 N/m and k_{2}= 5.0 N/m? A) 2.5 rad/s B) 3.5 rad/s C) 0.40 rad/s D) 0.56 rad/sFree

Multiple Choice

Q 29Q 29

A 1.6-kg block on a horizontal frictionless surface is attached to an ideal massless spring whose spring constant is 190 N/m. The block is pulled from its equilibrium position at x = 0.00 m to a displacement x = +0.080 m and is released from rest. The block then executes simple harmonic motion along the horizontal x-axis. What is the velocity of the block at time t = 0.40 s?
A) 0.82 m/s
B) -0.82 m/s
C) 0.30 m/s
D) -0.30 m/s
E) 0.00 m/s

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Multiple Choice

Q 30Q 30

A 0.28-kg block on a horizontal frictionless surface is attached to an ideal massless spring whose spring constant is 500 N/m. The block is pulled from its equilibrium position at x = 0.00 m to a displacement x = +0.080 m and is released from rest. The block then executes simple harmonic motion along the horizontal x-axis. When the displacement is x = -0.052 m, find the acceleration of the block.
A) 92 m/s

^{2}B) 46 m/s^{2}C) 69 m/s^{2}D) 230 m/s^{2}E) 280 m/s^{2}Free

Multiple Choice

Q 31Q 31

In the figure, two masses, M = 16 kg and m = 12.8.0 kg, are connected to a very light rigid bar and are attached to an ideal massless spring of spring constant 100 N/m. The system is set into oscillation with an amplitude of 78 cm. At the instant when the acceleration is at its maximum, the 16-kg mass separates from the 12.8.0-kg mass, which then remains attached to the spring and continues to oscillate. What will be the amplitude of oscillation of the 12.8.0-kg mass?
A) 78 cm
B) 62 cm
C) 35 cm
D) 98 cm
E) 180 cm

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Multiple Choice

Q 32Q 32

A 2.00-kg object is attached to an ideal massless horizontal spring of spring constant 100.0 N/m and is at rest on a frictionless horizontal table. The spring is aligned along the x-axis and is fixed to a peg in the table. Suddenly this mass is struck by another 2.00-kg object traveling along the x-axis at 3.00 m/s, and the two masses stick together. What are the amplitude and period of the oscillations that result from this collision?
A) 0.300 m, 1.26 s
B) 0.300 m, 0.889 s
C) 0.424 m, 0.889 s
D) 0.424 m, 1.26 s
E) 0.424 m, 5.00 s

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Multiple Choice

Q 33Q 33

A 0.25 kg ideal harmonic oscillator has a total mechanical energy of 4.0 J. If the oscillation amplitude is 20.0 cm, what is the oscillation frequency?
A) 4.5 Hz
B) 1.4 Hz
C) 2.3 Hz
D) 3.2 Hz

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Multiple Choice

Q 34Q 34

A 0.50-kg object is attached to an ideal massless spring of spring constant 20 N/m along a horizontal, frictionless surface. The object oscillates in simple harmonic motion and has a speed of 1.5 m/s at the equilibrium position.
(a) What is the amplitude of vibration?
(b) At what location are the kinetic energy and the potential energy of the system the same?

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Q 35Q 35

A 1.5-kg mass attached to an ideal massless spring with a spring constant of 20.0 N/m oscillates on a horizontal, frictionless track. At time t = 0.00 s, the mass is released from rest at x = 10.0 cm. (That is, the spring is stretched by 10.0 cm.)
(a) Find the frequency of the oscillations.
(b) Determine the maximum speed of the mass. At what point in the motion does the maximum speed occur?
(c) What is the maximum acceleration of the mass? At what point in the motion does the maximum acceleration occur?
(d) Determine the total energy of the oscillating system.
(e) Express the displacement x as a function of time t.

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Essay

Q 36Q 36

A 0.025-kg block on a horizontal frictionless surface is attached to an ideal massless spring whose spring constant is 150 N/m. The block is pulled from its equilibrium position at x = 0.00 m to a displacement x = +0.080 m and is released from rest. The block then executes simple harmonic motion along the horizontal x-axis. When the displacement is x = 0.024 m, what is the kinetic energy of the block?
A) 0.44 J
B) 0.41 J
C) 0.46 J
D) 0.49 J
E) 0.52 J

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Multiple Choice

Q 37Q 37

An object of mass 6.8 kg is attached to an ideal massless spring of spring constant 1690 N/m. The object is Calculate the maximum speed the object reaches during its motion.

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Short Answer

Q 38Q 38

An object weighing 44.1 N hangs from a vertical massless ideal spring. When set in vertical motion, the object obeys the equation y(t) = (6.20 cm) cos[(2.74 rad/s)t - 1.40].
(a) Find the time for this object to vibrate one complete cycle.
(b) What are the maximum speed and maximum acceleration of the object.
(c) What is the TOTAL distance the object moves through in one cycle.
(d) Find the maximum kinetic energy of the object.
(e) What is the spring constant of the spring.

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Q 39Q 39

A frictionless simple pendulum on Earth has a period of 1.75 s. On Planet X its period is 2.14 s. What is the acceleration due to gravity on Planet X?

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Short Answer

Q 40Q 40

In the figure, a 0.24-kg ball is suspended from a very light string 9.79 m long and is pulled slightly to the left. As the ball swings without friction through the lowest part of its motion it encounters an ideal massless spring attached to the wall. The spring pushes against the ball and eventually the ball is returned to its original starting position. Find the time for one complete cycle of this motion if the spring constant of the spring is 21 N/m. (Assume that once the pendulum ball hits the spring there is no effect due to the vertical movement of the ball.)

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Short Answer

Q 41Q 41

A long thin uniform rod of length 1.50 m is to be suspended from a frictionless pivot located at some point along the rod so that its pendulum motion takes 3.00 s. How far from the center of the rod should the pivot be located?
A) 7.98 cm
B) 7.52 cm
C) 8.73 cm
D) 8.40 cm
E) 23.4 cm

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Multiple Choice

Q 42Q 42

A uniform meter stick is freely pivoted about the 0.20-m mark. If it is allowed to swing in a vertical plane with a small amplitude and friction, what is the frequency of its oscillations?
A) 0.55 Hz
B) 0.66 Hz
C) 0.92 Hz
D) 1.1 Hz
E) 1.3 Hz

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Multiple Choice

Q 43Q 43

A large stick is pivoted about one end and allowed to swing back and forth with no friction as a physical pendulum. The mass of the stick is 5.40 kg and its center of gravity (found by finding its balance point) is 1.80 m from the pivot. If the period of the swinging stick is 6.90 seconds, what is the moment of inertia of the stick about an axis through the pivot?

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Short Answer

Q 44Q 44

The amplitude of a lightly damped harmonic oscillator decreases from 60.0 cm to 40.0 cm in 10.0 s. What will be the amplitude of the harmonic oscillator after another 10.0 s passes?
A) 20.0 cm
B) 167 cm
C) 30.0 cm
D) 0.00 cm
E) 26.7 cm

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Multiple Choice

Q 45Q 45

A lightly damped harmonic oscillator, with a damping force proportional to its speed, is oscillating with an amplitude of 0.500 cm at time t = 0. When t = 8.20 s, the amplitude has died down to 0.400 cm. At what value of t will the oscillations have an amplitude of 0.250 cm?
A) 18.5 s
B) 20.5 s
C) 16.5 s
D) 25.5 s
E) 5.13 s

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Multiple Choice

Q 46Q 46

An ideal massless spring with a spring constant of 2.00 N/m is attached to an object of 75.0 g. The system has a small amount of damping. If the amplitude of the oscillations decreases from 10.0 mm to 5.00 mm in 15.0 s, what is the magnitude of the damping constant b?
A) 0.00693 kg/s
B) 0.0462 kg/s
C) 0.00762 kg/s
D) 0.0100 kg/s
E) 0.00857 kg/s

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Multiple Choice

Q 47Q 47

A 2.15 kg lightly damped harmonic oscillator has an angular oscillation frequency of 0.261 rad/s. If the maximum displacement of 2.0 m occurs when t = 0.00 s, and the damping constant b is 0.74 kg/s what is the object's displacement when t = 4.01 s?
A) 0.50 m
B) 0.43 m
C) 0.58 m
D) 0.65 m

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Multiple Choice

Q 48Q 48

A 25 kg object is undergoing lightly damped harmonic oscillations. If the maximum displacement of the object from its equilibrium point drops to 1/3 its original value in 1.8 s, what is the value of the damping constant b?
A) 31 kg/s
B) 34 kg/s
C) 37 kg/s
D) 40 kg/s

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Multiple Choice

Q 49Q 49

A 5.0-kg block is attached to an ideal massless spring whose spring constant is 125 N/m. The block is pulled from its equilibrium position at x = 0.00 m to a position at x = +0.687 m and is released from rest. The block then executes lightly damped oscillation along the x-axis, and the damping force is proportional to the velocity. When the block first returns to x = 0.00 m, its x component of velocity is -2.0 m/s and its x component of acceleration is +5.6 m/s

^{2}. (a) What is the magnitude of the acceleration of the block upon release at x = +0.687 m. (b) Find the damping constant b.Free

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