Physics 2: Unit 1 MC

D) 1/3 as great

GTC 12-1 Jess has a resting pulse of 50 heartbeats per minute. When Jess sprints down the track, her pulse increases to 150 beats per minute. Compared to when she is at rest, the oscillation period of her heart when she is sprinting is A) 9 times as great B) 3 times as great C) the same D) 1/3 as great E) 1/9 as great

D) zero

GTC 12-10 You measure the oscillation frequency of a physical pendulum when it is pivoted at one end. You then rearrange the experiment so that the physical pendulum is pivoted around its center of mass. Compared to the frequency when it is pivoted at one end, the frequency when it is pivoted at the center of mass is A) greater B) the same C) less, but not zero D) zero E) not enough information given to decide

E) 2.0 km/s The wave is moving in the +x direction because the signs (of x and t) are opposite

The equation of a traveling wave is y(x,t) = 0.02 cos(0.25x - 500t), where the units are SI. The velocity of the wave is A) 4.0 m/s B) 10 m/s C) 0.13 km/s D) 0.50 km/s E) 2.0 km/s What direction is the wave moving?

B) Fastest on the thinnest string

The four strings of a musical instrument are all made of the same material and are under the same tension (to prevent warping), but have different thicknesses. On which do the waves move the fastest? A) Fastest on the thickest string B) Fastest on the thinnest string C) Same speed on all strings

D) 512 Hz

The fundamental frequency of a pipe that has one end closed is 256Hz. When both ends of the same pipe are opened, the fundamental frequency is A) 64 Hz B) 128 Hz C) 256 Hz D) 512 Hz E) 1.02 kHz

D) (2)^1/2 * f1

The fundamental frequency of a vibrating string f1. If the tension in the string is doubled, the fundamental frequency becomes A) f1/2 B) f1 / (2)^1/2 C) f1 D) (2)^1/2 * f1 E) 2*f1

A) 500 Hz ; 1500 Hz

The human vocal tract can be thought of as a tube that is open at one end. If the the length of this tube is 17 cm, what are the lowest two harmonics? (the velocity of sound in air is 340 m/s) A) 500 Hz ; 1500 Hz B) 500 Hz ; 1000 Hz C) 1000 Hz ; 2000 Hz D) 1000 Hz ; 3000 Hz E) 1500 Hz ; 2500 Hz

B) the wave speeds are different

Tightening the tuning screw on a guitar string produces different pitch (frequency) sound waves because: A) the wavelengths of the fundamental nodes of vibration are different B) the wave speeds are different C) both of the above D) none of the above

D) 3.0 Hz

Two whistles produce sounds with wavelengths 2.40m and 3.30m. What is the beat frequency produced? (the speed of sound is 340 m/s) A) 0.1 Hz B) 1.0 Hz C) 2.0 Hz D) 3.0 Hz E) 4.0 Hz

E) 4 times as great

What do you think? In a typical adult at rest, the heart beast 60 times per minute. During moderate cardiovascular exercise the heart rate can increase to 120 beats per minute. If the walls of the heart move in and out by the same distance for both heart rates, how does the maximum acceleration of the heart walls during moderate exercise compare to that when resting? A) 1/4 as great B) 1/2 as great C) the same D) twice as great E) 4 times as great

A) Transverse Wave

When fans in a stadium do "The Wave," it is like a: A) Transverse Wave B) Longitudinal Wave

A) Greater than

If a simple pendulum is brought to the surface of the moon, it's period would be: A) Greater than B) Less than C) The same as

D) 2T

If the period of a simple pendulum is T and you increase its length so that it is 4 times larger, what will the new period be? A) T/2 B) T/4 C) 4T D) 2T E) It is unchanged

C. Push the block to position 𝑥 = −A and release it E. 𝜋 rad

A block attached to a spring is pushed a distance 𝐴A to the right and then released. The block rests on a frictionless horizontal surface, so undergoes simple harmonic motion. The position versus time graph of the block is shown in Figure 1. 1. Which modifications to the initial conditions will produce the oscillations represented in Figure 2? A. Start the block at the equilibrium length of the spring and give it a kick to the left sufficient to produce oscillations of amplitude A. B. Start the block at the equilibrium length of the spring and give it a kick to the right sufficient to produce oscillations of amplitude A. C. Push the block to position 𝑥 = −A and release it. Under the original conditions, the position 𝑥(𝑡)x(t) of the block is given by the function 𝑥(𝑡)=𝐴cos(𝜔𝑡)x(t)=Acos⁡(ωt) where 𝜔ω is the angular frequency of oscillation. Under the modified conditions, the new position function 𝑥′(𝑡)x′(t) is 𝑥′(𝑡)=𝐴cos(𝜔𝑡+𝜙)x′(t)=Acos⁡(ωt+ϕ) where 𝜙ϕ is the phase angle 2. Select the correct phase angle 𝜙ϕ for the position function of the modified system. A. 0 rad B. 𝜋/4 rad C. 𝜋/2 rad D. 3𝜋/4 rad E. 𝜋 rad

b) increase by a factor of 2

A block of mass m attached to a horizontally mounted spring with spring constant k undergoes simple harmonic motion in a frictionless surface. How would the max speed of the block be affected of the spring constant was increased by a factor of 4 while holding the amplitude of oscillation constant? a) it would increase by a factor of 4 b) increase by a factor of 2 c) decrease by a factor of 1/4 d) decreased by a factor of 1/4 e) remain unchanged

increases frequency: increase K does not increase frequency: increase A, increase m, increase phi

A block of mass m attached to the end of a spring of spring constant k undergoes simple harmonic motions with amplitude (A) and angular frequency (w). The position of the block is described by a cosine function with an initial phase angle phi = 0 Suppose that each of the variables m, k, A, and theta is increase in value. Classify which increases produce an increase in the frequency of oscillation and which do not.

S

A block on a spring slides on a horizontal frictionless surface in simple harmonic motion The corresponding displacement versus time graph of the block is shown At which point is the spring potential energy U(spring) greatest? P Q R S T U V

V

A block on a spring slides on a horizontal frictionless surface in simple harmonic motion The corresponding displacement versus time graph of the block is shown At which point is the velocity of the block positive and the acceleration negative? P Q R S T U V

B) Down

A simple pendulum is used as the timing element in a clock as shown. an adjustment screw is used to make the pendulum shorter (longer) by moving the weight up (down) along the shaft that connects it to the pivot. If the clock is running too fast, the weight needs to be moved A) Up B) Down

𝑓/2

A small marble attached to a massless thread is hung from a horizontal support. When the marble is pulled back a small distance from equilibrium and released, it swings in simple harmonic motion with a frequency f. What is the frequency of the pendulum if the length of the thread is increased by a factor of 4, but the marble is still released in the same way? 4𝑓 2𝑓 𝑓 𝑓/2 𝑓/4

3/4T e) no change in the answer

A small object is attached to a horizontal spring, pushed to position x = -A, and then released. The object undergoes simple harmonic motion with period T. How long does it take for the object to travel a total distance of 3A? T 1/2T 3/4T 5/4T 1/4T Now assume that the object is initially at x = 0 and given an initial velocity such that it oscillate with the same amplitude A. Relative to your previous answer, how much does the time to travel 3A change under these new conditions? a) this time will increase by 1/2T b) this time will increase by 1/4T c) this time will decrease by 1/2T d) this time will decrease by 1/4T e) no change in the answer

B) 70 Hz

A string fastened at both ends resonates at 420 Hz and 490 Hz, with no resonance frequencies in between. What is the fundamental resonance frequency? A) 60 Hz B) 70 Hz C) 140 Hz D) 420 Hz E) 490 Hz F) Unable to determine based on information given

B) 2v

A string under tension carries transverse waves traveling at speed v. If the same string is under four times the tension, what is the speed? A) v B) 2v C) v/2 D) 4v E) v/4

C) Wave number

A wave on a string is generated by whipping it up and down. If the tension on the string is doubled while the student is whipping the string at a constant rate, which of the following will change as well? A) Amplitude of the wave B) Angular frequency C) Wave number D) None of the above

m2 > m4 > m3 > m1

Consider four different oscillating systems, indexed using 𝑖=1,2,3,4 . Each system consists of a block of mass 𝑚i moving at speed 𝑣i on a frictionless surface while attached to an ideal, horizontally fixed spring with a force constant of 𝑘i . Let 𝑥 denote the displacement of the block from its equilibrium position. Order the systems from largest total mechanical energy to smallest. 1) m1= 0.5KG k2=500 N/m amplitude A = 0.02 m 2) m2= 0.6KG k2=300 N/m v2= 1 m/s . when passing through equilibrium 3) m3= 1.2KG k3=400 N/m v3= 0.5 m/s . when passing through x= -0.01 m 4) m4= 2 KG k4=200 N/m v4= 0.2 m/s . when passing through x=-0.05 m

A) underdamped

GTC 12-11 A block is attached to an ideal spring, The system of block and spring is critically damped: When the block is displaced from equilibrium and released, the block returns smoothly to equilibrium in the minimum time possible and does not overshoot equilibrium. If you replace the block with a new one of twice the mass, but the damping coefficient and spring constant remain the same, what kind of oscillations will result? A) underdamped B) critically damped C) overdamped D) not enough information given to decide

E) remain unchanged

GTC 12-2 Suppose you were to increase the amplitude of the oscillation in example 12-3 by a factor of 4, from 2.0 x 10^-2 to 8.0 x 10^-2 m. The spring constant and mass remain the same as in example 12-3. This would cause the frequency of the oscillation to A) increase by a factor of 4 B) increase by a factor of 2 C) decrease by a factor of 1/4 D) decrease by a factor of 1/2 E) remain unchanged

B) increase by a factor of 2

GTC 12-3 Suppose you were to increase the spring constant of the spring in example 12-3 by a factor of 4, from 1.8 x 10^2 to 7.2 x 10^2 N/m. The mass and amplitude remain the same as in example 12-3. This would cause the maximum speed of the block during the oscillation to A) increase by a factor of 4 B) increase by a factor of 2 C) decrease by a factor of 1/4 D) decrease by a factor of 1/2 E) remain unchanged

D) -A = -2.0 x 10^-2 m

GTC 12-4 Suppose you were to change the phase angle in example 12-3 to phase angle=pi. The spring constant, mass, and amplitude remain the same as in example 12-3. This would change the displacement x of the block at t=0 to be A) A= 2.0 x 10^-2 m B) positive, but less than A C) zero D) -A = -2.0 x 10^-2 m E) negative, but between zero and -A

b > d > c > a

GTC 12-5 Consider four different systems, each made of a block attached to an ideal horizontal spring. Rank them in order of their total mechanical energy, from largest to smallest value. (a) block mass 0.50kg and spring constant 5.0 x 10^2 N/m, with amplitude 0.020m (b) block mass 0.60kg and spring constant 3.0 x 10^2 N/m, with speed 1.0 m/s when passing through equilibrium (c) block mass 1.2kg and spring constant 4.0 x 10^2 N/m, with speed 0.50 m/s when passing through x= -0.010 m (d) block mass 2.0kg and spring constant 2.0 x 10^2 N/m, with speed 0.20 m/s when passing through z = 0.050 m

D) 0.30 Hz

GTC 12-6 A small marble is attached to a thread that has a negligible mass and is hung from a support. When the marble is pulled back at a small distance and released, it swings in simple harmonic motion with a frequency of 0.60 Hz. What is the frequency of the pendulum after the length of the thread is increased by a factor of 4 but the marble is released in the same way? A) 2.4 Hz B) 1.2 Hz C) 0.60 Hz D) 0.30 Hz E) 0.15 Hz

C) 0.60 Hz

GTC 12-7 A small marble is attached to a thread that has a negligible mass and is hung from a support. When the marble is pulled back at a small distance and released, it swings in simple harmonic motion with a frequency of 0.60 Hz. If the marble is replaced by one that has four times the mass of the original one, and the new marble is pulled back by half the distance of the original marble before being released, what is the new frequency? Assume that the length of the thread remains the same. A) 2.4 Hz B) 1.2 Hz C) 0.60 Hz D) 0.30 Hz E) 0.15 Hz

A) greater than the period of the leg

GTC 12-9 A uniform rod has the same length and mass as the leg in the previous example. When supported at one end and allowed to rotate, would the period of this rod be A) greater than the period of the leg B) the same as the period of the leg C) less than the period of the leg D) not enough information given to decide

(e) none of these

GTC 13-2: A person with normal hearing can hear sound waves that range in frequency from approximately 20 Hz to 20 kHz (1 kHz = 10^3 Hz) Compared to a 20-Hz sound wave, a 20-kHz sound wave has (a) a shorter wavelength and a faster propagation speed; (b) a longer wavelength and a faster propagation speed; (c) a shorter wavelength and a slower propagation speed; (d) a longer wavelength and a faster propagation speed; (e) none of these

b) move inward towards the fingers;

GTC 13-4: If you increase the frequency at which the fingers in Figure 13-15 dip into the water, would the interference pattern (a) move outward away from the fingers; (b) move inward towards the fingers; (c) remain unchanged; or (d) any of these, depending on the value of the frequency?

(c) vertical, horizontal

GTC: 13-1 Choose the selection that correctly fills in the blanks in the following sentence: In the wave shown in Figure 13-2a the restoring force on a piece of the rope acts in the _____________ direction, and in the wave shown in the Figure 13-2b the restoring force on a piece of the spring acts in the _____________ direction. (a) vertical, vertical (b) horizontal, vertical (c) vertical, horizontal (d) horizontal, horizontal (e) any of these, depending on circumstances

C) 443 Hz

If the A string on a guitar is in tune it plays at 440 Hz. When a tuning fork with a natural frequency of 440 Hz is struck at the same time the string is played, a beat is heard every 1/3 second. As the guitarist tightens the string, the period of the beats heard decreases (shorter time interval between beats). What frequency was the guitar playing before the string was tightened? A) 440.33 Hz B) 439.67 Hz C) 443 Hz D) 447 Hz

E) Need more information

If the A string on a guitar is in tune it plays at 440 Hz. When a tuning fork with a natural frequency of 440 Hz is struck at the same time the string is played, a beat is heard every 1/3 second. What frequency is the guitar string playing? A) 440.33 Hz B) 439.67 Hz C) 443 Hz D) 447 Hz E) Need more information

D) v is unchanged and wavelength is halved

If you double the frequency of a wave on a string (for example, by oscillating its end up-and-down more rapidly), what happens to the wave speed and wavelengths of the traveling waves? A) v is doubled and wavelength is halved B) v is doubled and wavelength is doubled C) v is unchanged and wavelength is doubled D) v is unchanged and wavelength is halved E) v is halved and wavelength is unchanged F) v is halved and wavelength is halved

e) male mosquitoes can detect flying females

Male and female mosquitoes emit different sound frequencies while in flight, and their antennae are sensitive to different frequencies. The sound made by male mosquitoes in flight is close to 650 Hz, whereas the sound made by females is close to 400 Hz. The natural frequency of males' antennae is about 400 Hz, whereas that of females is about 200 Hz. Biologists suspect that some mosquitoes can detect the presence of other mosquitoes based on nerve signals generated when their antennae vibrate strongly. Assuming that the biologists are correct, the emitted frequencies of flying mosquitoes and the vibrational frequencies of their antennae suggest it is likely that a) female mosquitoes can detect flying members of both sexes. b) male mosquitoes can detect flying males. c) both sexes can detect flying females. d) female mosquitoes can detect flying females. e) male mosquitoes can detect flying females. f) female mosquitoes can detect flying males.

A) the wavelengths of the fundamental nodes of vibration are different

Playing a string on different frets of a guitar produces different pitch (frequency) sound waves because: A) the wavelengths of the fundamental nodes of vibration are different B) the wave speeds are different C) both of the above D) none of the above

B) the wave speeds are different

Playing different strings on a guitar produces different pitch (frequency) sound waves because: A) the wavelengths of the fundamental nodes of vibration are different B) the wave speeds are different C) both of the above D) none of the above

D) 2

Replacing an object attached to a spring with an object having 1/4 the original mass will change the frequency of oscillation of the system by a factor of A) 1/4 B) 1/2 C) 1, or no change D) 2 E) 4

A) lightly bouncing on a trampoline when your feet do not leave the canvas B) a pendulum in a grandfather clock C) a child gently swinging on a playground swing at small angles

Select examples of simple harmonic motion that can be observed in everyday life. A) lightly bouncing on a trampoline when your feet do not leave the canvas B) a pendulum in a grandfather clock C) a child gently swinging on a playground swing at small angles D) dribbling a basketball at a steady rate E) a yo-yo moving up and down in a steady pattern F) a spinning top

e) cannot be determined

Select the option that correctly orders the pendulums according to mass a) B < D < C < A b) A < C < D < B c) B < C < A < D d) D < A < C < B e) cannot be determined

D) The restoring force acting on the oscillator obeys Hooke's law, making it a conservative force

Which of the following choices explains why mechanical energy is always conserved in an ideal simple harmonic oscillator? A) Springs only use conservative energy, so an oscillators mechanical energy must be conserved B) The amplitude of the oscillations always remain constant, so the energy never changes C) Kinetic energy and spring potential energy are always positive because they both have a term that is squared, so energy cannot be taken away D) The restoring force acting on the oscillator obeys Hooke's law, making it a conservative force E) Springs cannot absorb energy, so energy is not removed from the system F) The force of friction does not act on an ideal oscillator, so energy remains constant

a) Bat 1

Which of the two softball bats will show a longer period of oscillation when swinging in simple harmonic motion from the knob end of the handle? a) Bat 1 b) Bat 2 c) same for both

A) It decreases to 1/4 its original value

You are standing 4 m from a speaker that is emitting a sound wave of 400 Hz in all directions. If you move to a position 8 m away from the speaker, what happens to the intensity you detect? A) It decreases to 1/4 its original value B) It decreases to 1/2 its original value C) It remains the same D) It increases to 2 times greater than its original value E) It increases to 4 times greater than its original value