1. Intro to Physics Units

Introduction to Units

1. Intro to Physics Units

# Introduction to Units - Video Tutorials & Practice Problems

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intro

## Introduction to Physics Channel

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concept

## Introduction to Units & the SI System

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concept

## Metric Prefixes

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4

Problem

ProblemThe earth's circumference is approximately 40.1 Mm (megameters). What is this circumference in kilometers?

A

0.0401 km

B

40,100,000 km

C

40,100 km

D

0.00401 km

5

Problem

ProblemAstronomers often detect radio waves with wavelengths of 3,000,000,000 nm. What is this wavelength expressed in decameters (dam)?

A

3 dam

B

0.3 dam

C

30 dam

D

0.03 dam

6

concept

## Scientific Notation

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7

Problem

ProblemRewrite 0.00016 kg in scientific notation.

A

1.6×10

^{-4}B

16×10

^{-3}C

1.6×10

^{4}D

1.6×10

^{-3}8

Problem

ProblemRewrite 299,800,000 m/s in scientific notation.

A

2.998×10

^{5}B

3.00×10

^{8}C

3.00×10

^{5}D

2.998×10

^{-5}9

example

## Rewriting in Scientific Notation

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10

Problem

ProblemRewrite 3.41 × 10^{−4} in standard form:

A

0.000341

B

34,100

C

0.0000341

D

3,410

11

Problem

ProblemRewrite 9.98 × 10^{7} in standard form.

A

0.000000998

B

0.0000000998

C

9,980,000,000

D

99,800,000

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PRACTICE PROBLEMS AND ACTIVITIES (124)

- The position of an object is given by 𝓍 = At + Bt², where 𝓍 is in meters and t is in seconds.(a) What are th...
- Write the following numbers in powers of 10 notation:(e) 0.219
- Write out the following numbers in full with the correct number of zeros:(c) 2.5 x 10⁻¹
- (b) Is this particle curving upward, curving downward, or moving in a straight line?
- Time intervals measured with a physical stopwatch typically have an uncertainty of about 0.2 s, due to human r...
- A watch manufacturer claims that its watches gain or lose no more than 9 seconds in a year. How accurate are t...
- Write the following as full (decimal) numbers without prefixes on the units:(e) 22.5 nm
- Express the following using the prefixes of Table 1–4: 18 x 10² bucks and
- A demented scientist creates a new temperature scale, the 'Z scale.' He decides to call the boiling point of n...
- The lowest and highest natural temperatures ever recorded on earth are −129°F in Antarctica and 134°F in Death...
- The age of the universe is thought to be about 14 billion years. Assuming two significant figures, write this ...
- The Sun, on average, is 93 million miles from Earth. How many meters is this? Express(b) using a metric prefix...
- An alien spacecraft is flying overhead at a great distance as you stand in your backyard. You see its searchli...
- The positive muon (µ+), an unstable particle, lives on average 2.20 * 10^-6 s (measured in its own frame of re...
- The positive muon (µ+), an unstable particle, lives on average 2.20 * 10^-6 s (measured in its own frame of re...
- (b) A force is applied to a particle along its direction of motion. At what speed is the magnitude of force re...
- A proton has momentum with magnitude p0 when its speed is 0.400c. In terms of p0, what is the magnitude of the...
- Suppose the two lightning bolts shown in Fig. 37.5a are simultaneous to an observer on the train. Show that th...
- X rays with initial wavelength 0.0665 nm undergo Compton scattering. What is the longest wavelength found in t...
- The cathode-ray tubes that generated the picture in early color televisions were sources of x rays. If the acc...
- The photoelectric work function of potassium is 2.3 eV. If light that has a wavelength of 190 nm falls on pota...
- The photoelectric work function of potassium is 2.3 eV. If light that has a wavelength of 190 nm falls on pota...
- What would the minimum work function for a metal have to be for visible light (380–750 nm) to eject photoelect...
- The photoelectric threshold wavelength of a tungsten surface is 272 nm. Calculate the maximum kinetic energy o...
- A photon has momentum of magnitude 8.24 * 10-28 kg # m>s. (b) What is the wavelength of this photon? In wha...
- A laser used to weld detached retinas emits light with a wavelength of 652 nm in pulses that are 20.0 ms in du...
- A photon of green light has a wavelength of 520 nm. Find the photon's frequency, magnitude of momentum, and en...
- (a) The energy of the 2s state of lithium is -5.391 eV. Calculate the value of Zeff for this state.
- (b) Estimate the energy of the least strongly bound level in the L shell of N2+.
- (a) The doubly charged ion N2+ is formed by removing two electrons from a nitrogen atom. What is the ground-st...
- The energies of the 4s, 4p, and 4d states of potassium are given in Example 41.10. Calculate Zeff for each sta...
- The 5s electron in rubidium (Rb) sees an effective charge of 2.771e. Calculate the ionization energy of this e...
- A hydrogen atom in a particular orbital angular momentum state is found to have j quantum numbers 7 2 and 9 2 ...
- Calculate the energy difference between the ms = 1 2 ('spin up') and ms = - 1 2 ('spin down') levels of a hydr...
- The hyperfine interaction in a hydrogen atom between the magnetic dipole moment of the proton and the spin mag...
- (a) If you treat an electron as a classical spherical object with a radius of 1.0 * 10-17 m, what angular spee...
- A hydrogen atom in the 5g state is placed in a magnetic field of 0.600 T that is in the z@direction. (a) Into ...
- A hydrogen atom in a 3p state is placed in a uniform external magnetic field B S . Consider the interaction of...
- Pure germanium has a band gap of 0.67 eV. The Fermi energy is in the middle of the gap. (a) For temperatures o...
- At the Fermi temperature T_F, E_F = kT_F (see Exercise 42.22). When T = T_F, what is the probability that a st...
- CP Silver has a Fermi energy of 5.48 eV. Calculate the electron contribution to the molar heat capacity at con...
- Calculate the density of states g(E) for the free-electron model of a metal if E = 7.0 eV and V = 1.0 cm^3 . E...
- The maximum wavelength of light that a certain silicon photocell can detect is 1.11 mm. (b) Explain why pure s...
- The maximum wavelength of light that a certain silicon photocell can detect is 1.11 mm. (a) What is the energy...
- The average kinetic energy of an ideal-gas atom or molecule is (3/2)kT, where T is the Kelvin temperature (Cha...
- CP The rotational energy levels of CO are calculated in Example 42.2. If the energy of the rotating molecule i...
- Measurements on a certain isotope tell you that the decay rate decreases from 8318 decays/min to 3091 decays/m...
- The unstable isotope 40K is used for dating rock samples. Its half-life is 1.28x10^9 y. (a) How many decays oc...
- The common isotope of uranium, 238U, has a halflife of 4.47x10^9 years, decaying to 234Th by alpha emission. (...
- Radioactive isotopes used in cancer therapy have a 'shelf-life,' like pharmaceuticals used in chemotherapy. Ju...
- What particle (a particle, electron, or positron) is emitted in the following radioactive decays? (a) 27 14SiS...
- The atomic mass of 14C is 14.003242 u. Show that the b- decay of 14C is energetically possible, and calculate ...
- What nuclide is produced in the following radioactive decays? (a) a decay of 239 94 Pu; (b) b- decay of 24 11N...
- (a) Is the decay nS p + b- + ve energetically possible? If not, explain why not. If so, calculate the total en...
- The most common isotope of uranium, 238 92U, has atomic mass 238.050788 u. Calculate (a) the mass defect; (b) ...
- Hydrogen atoms are placed in an external magnetic field. The protons can make transitions between states in wh...
- (a) What is the speed of a proton that has total energy 1000 GeV?
- (a) A high-energy beam of alpha particles collides with a stationary helium gas target. What must the total en...
- The magnetic field in a cyclotron that accelerates protons is 1.70 T. (a) How many times per second should the...
- Deuterons in a cyclotron travel in a circle with radius 32.0 cm just before emerging from the dees. The freque...
- An electron with a total energy of 30.0 GeV collides with a stationary positron. (a) What is the available ene...
- A proton and an antiproton annihilate, producing two photons. Find the energy, frequency, and wavelength of ea...
- CP Two equal-energy photons collide head-on and annihilate each other, producing a µ^+µ^- pair. The muon mass ...
- A neutral pion at rest decays into two photons. Find the energy, frequency, and wavelength of each photon. In ...
- "(I) Estimate the order of magnitude (power of 10) of: (b) 86.30 x 10³"
- "(II) Use Table 1–3 to estimate the total number of protons or neutrons in :(c) the human body"
- "(II) A typical atom has a diameter of about 1.0 x 10⁻¹⁰ m. (b) Approximately how many atoms are along a 1....
- (III) Many sailboats are docked at a marina 4.4 km away on the opposite side of a lake. You stare at one of th...
- Global positioning satellites (GPS) can be used to determine your position with great accuracy. If one of the ...
- If you walked north along one of Earth's lines of longitude until you had changed latitude by 1 minute of arc ...
- Determine the percent uncertainty in θ, and in sin θ, when θ = 75.0° ± 0.5°.
- Dimensional analysis. Waves on the surface of the ocean do not depend significantly on the properties of water...
- (II) Estimate how many books can be shelved in a college library with 6500 m² of floor space. Assume 8 shelves...
- (II) Estimate how long it would take one person to mow a football field using an ordinary home lawn mower (Fig...
- (II) A hiking trail is 270 km long through varying terrain. A group of hikers cover the first 49 km in two and...
- (II) Estimate the number of jelly beans in the jar of Fig. 1–13.<IMAGE>
- Recent findings in astrophysics suggest that the observable universe can be modeled as a sphere of radius R = ...
- (II) The diameter of the planet Mercury is 4879 km.(a) What is the surface area of Mercury?
- One mole of atoms consists of 6.02 x 10²³ individual atoms. If a mole of atoms were spread uniformly over the ...
- Relativistic Baseball. Calculate the magnitude of the force required to give a 0.145-kg baseball an accelerati...
- A proton (rest mass 1.67 * 10-27 kg) has total energy that is 4.00 times its rest energy. What are (a) the kin...
- Electrons are accelerated through a potential difference of 750 kV, so that their kinetic energy is 7.50 * 105...
- A particle has rest mass 6.64 * 10-27 kg and momentum 2.10 * 10-18 kg•m/s. (a) What is the total energy (kinet...
- Compute the kinetic energy of a proton (mass 1.67 * 10-27 kg) using both the nonrelativistic and relativistic ...
- Why Are We Bombarded by Muons? Muons are unstable subatomic particles that decay to electrons with a mean life...
- As you pilot your space utility vehicle at a constant speed toward the moon, a race pilot flies past you in he...
- A photon scatters in the backward direction 1f = 180°2 from a free proton that is initially at rest. What must...
- X rays with an initial wavelength of 0.900 * 10-10 m undergo Compton scattering. For what scattering angle is ...
- An electron and a positron are moving toward each other and each has speed 0.500c in the lab frame. (a) What i...
- Model a hydrogen atom as an electron in a cubical box with side length L. Set the value of L so that the volum...
- A photon is emitted when an electron in a threedimensional cubical box of side length 8.00 * 10-11 m makes a t...
- Consider an electron in the N shell. (a) What is the smallest orbital angular momentum it could have?
- Consider an electron in the N shell. (b) What is the largest orbital angular momentum it could have? Express y...
- Consider an electron in the N shell. (c) What is the largest orbital angular momentum this electron could have...
- Consider an electron in the N shell. (d) What is the largest spin angular momentum this electron could have in...
- The orbital angular momentum of an electron has a magnitude of 4.716 * 10-34 kg # m2>s. What is the angular...
- Calculate, in units of U, the magnitude of the maximum orbital angular momentum for an electron in a hydrogen ...
- A hydrogen atom is in a d state. In the absence of an external magnetic field, the states with different ml va...
- A hydrogen atom undergoes a transition from a 2p state to the 1s ground state. In the absence of a magnetic fi...
- Estimate the energy of the highest-l state for (a) the L shell of Be+ and (b) the N shell of Ca +.
- The energies for an electron in the K, L, and M shells of the tungsten atom are -69,500 eV, -12,000 eV, and -2...
- For the H2 molecule the equilibrium spacing of the two protons is 0.074 nm. The mass of a hydrogen atom is 1.6...
- During each of these processes, a photon of light is given up. In each process, what wavelength of light is gi...
- The H2 molecule has a moment of inertia of 4.6 * 10-48 kg•m^2 . What is the wavelength l of the photon absorbe...
- Two atoms of cesium (Cs) can form a Cs_2 molecule. The equilibrium distance between the nuclei in a Cs_2 molec...
- CP The rotational energy levels of CO are calculated in Example 42.2. If the energy of the rotating molecule i...
- (a) Suppose a piece of very pure germanium is to be used as a light detector by observing, through the absorpt...
- CP At a temperature of 290 K, a certain p-n junction has a saturation current IS = 0.500 mA. (a) Find the curr...
- (a) A forward-bias voltage of 15.0 mV produces a positive current of 9.25 mA through a p-n junction at 300 K. ...
- A Geiger counter is used to measure the decay of a radioactive isotope produced in a nuclear reactor. Initiall...
- It has become popular for some people to have yearly whole-body scans (CT scans, formerly called CAT scans) us...
- In a diagnostic x-ray procedure, 5.00x10^10 photons are absorbed by tissue with a mass of 0.600 kg. The x-ray ...
- Calculate the energy released in the fusion reaction
- A proton and an antiproton annihilate, producing two photons. Find the energy, frequency, and wavelength of ea...
- The starship Enterprise, of television and movie fame, is powered by combining matter and antimatter. If the e...
- Calculate the minimum beam energy in a proton-proton collider to initiate the p + p → p + p + η^0 reaction. Th...
- In Example 44.3 it was shown that a proton beam with an 800-GeV beam energy gives an available energy of 38.7 ...
- You work for a start-up company that is planning to use antiproton annihilation to produce radioactive isotope...
- A K^+ meson at rest decays into two p mesons. (a) What are the allowed combinations of π^0 , π^+, and π^- as d...
- How much energy is released when a µ^- muon at rest decays into an electron and two neutrinos? Neglect the sma...
- Table 44.3 shows that a Σ^0 decays into a Λ^0 and a photon. (a) Calculate the energy of the photon emitted in ...
- Table 44.3 shows that a Σ^0 decays into a Λ^0 and a photon. (b) What is the magnitude of the momentum of the p...
- If a Σ^+ at rest decays into a proton and a π^0 , what is the total kinetic energy of the decay products?
- What is the total kinetic energy of the decay products when an upsilon particle at rest decays to t^+ + t^-?