Physics for Beginners: Online Practice Test 1

Question 1

An object is released from rest and reaches \(17.6\unit{m/s}\) downward. About how long has it been falling if air resistance is negligible?

A\(1.8\unit{s}\)B\(8.0\unit{s}\)C\(0.56\unit{s}\)D\(3.6\unit{s}\)

Question 2

An ultraviolet photon and a visible-light photon are compared. Which has greater energy?

AThe visible-light photon, because visible light has the longer wavelength.BThe ultraviolet photon, because ultraviolet light has the higher frequency.CThey have equal energy because both travel at the same speed in a vacuum.DTheir energies cannot be compared unless their amplitudes are known.

Question 3

An object carrying \(2.0\unit{\mu C}\) moves through an electric potential difference with magnitude \(5.0\unit{V}\). What is the magnitude of its electric potential-energy change?

A\(10\unit{\mu J}\)B\(0.40\unit{\mu J}\)C\(2.5\unit{\mu J}\)D\(7.0\unit{\mu J}\)

Question 4

A constant force does \(1.5\times10^{2}\unit{J}\) of work while acting parallel to a \(5.0\unit{m}\) displacement. What is the force magnitude?

A\(750\unit{N}\)B\(30\unit{N}\)C\(155\unit{N}\)D\(0.033\unit{N}\)

Question 5

A spring launcher remains in its Hooke's-law range while its compression doubles. How does the stored elastic energy change?

AIt becomes twice as large.BIt stays unchanged.CIt becomes half as large.DIt becomes four times as large.

Question 6

Take east as the positive direction. A runner is at \(x=12\unit{m}\) when \(t=2.0\unit{s}\) and at \(x=-18\unit{m}\) when \(t=8.0\unit{s}\). What is the runner's average velocity between these observations?

A\(30\unit{m/s}\) westB\(3.8\unit{m/s}\) westC\(5.0\unit{m/s}\) eastD\(5.0\unit{m/s}\) west

Question 7

A perpendicular force acts \(0.60\unit{m}\) from a pivot and produces \(18\unit{N\,m}\) of torque. What is the force magnitude?

Force is perpendicular to the lever.

A\(30\unit{N}\)B\(18\unit{N}\)C\(11\unit{N}\)D\(0.033\unit{N}\)

Question 8

A coil is replaced by one with twice as many turns while the rate of magnetic-flux change per turn remains the same. What happens to the magnitude of the induced emf?

AIt is cut in half.BIt becomes zero.CIt stays the same.DIt doubles.

Question 9

A small motor draws \(2.0\unit{A}\) from a \(12\unit{V}\) supply. What electrical power enters the motor?

A\(24\unit{W}\)B\(14\unit{W}\)C\(6.0\unit{W}\)D\(48\unit{W}\)

Question 10

A compass needle turns when it is placed near a straight wire carrying a steady current. What causes the needle to turn?

AThe needle must point in the same direction as the conventional current.BThe wire's field attracts one compass pole but exerts no force on the other pole.CThe current produces a magnetic field that exerts a torque on the compass needle.DA magnetic field exists around the wire only while the current is changing.

Question 11

A laboratory oscillator keeps the same spring while its attached mass becomes 4 times larger. How does its period change?

AThe period becomes twice as large.BThe period does not change.CThe period is cut in half.DThe period becomes four times as large.

Question 12

A nuclide has a \(5.0\unit{h}\) half-life. How long does it take for the number of undecayed nuclei to fall to one sixteenth of the initial number?

A\(20\unit{h}\)B\(16\unit{h}\)C\(5.0\unit{h}\)D\(80\unit{h}\)

Question 13

A thermometer is left in contact with a liquid sample until its reading stops changing. What condition has been reached?

AThe thermometer and liquid now have equal internal energies.BThe thermometer now contains the same amount of heat as the liquid.CThe thermometer and liquid are in approximate thermal equilibrium.DThe liquid's temperature must now be \(0^\circ\mathrm{C}\).

Question 14

A wheel turns at \(7.0\unit{rad/s}\). A reflector on the rim moves at \(2.45\unit{m/s}\). What is the wheel's radius?

A\(2.9\unit{m}\)B\(0.70\unit{m}\)C\(0.35\unit{m}\)D\(17\unit{m}\)

Question 15

A calculation gives the unit \(\mathrm{kg\,m^2/s^2}\). Which named SI unit is equivalent to it?

Atesla (T)Bjoule (J)Ccoulomb (C)Dpascal (Pa)

Question 16

A \(5.0\unit{kg}\) camera pod follows a circular path at \(6.0\unit{m/s}\). The net force toward the center is \(45\unit{N}\). What is the radius of the path?

A\(1.8\times10^{2}\unit{m}\)B\(0.25\unit{m}\)C\(8.0\unit{m}\)D\(4.0\unit{m}\)

Question 17

A spring oscillator reaches its greatest displacement to the right. Which velocity-and-acceleration description is correct?

The block is shown at its greatest displacement to the right.

AVelocity points right, and acceleration is zero.BVelocity is greatest, and acceleration points left.CVelocity is zero, and acceleration points left.DVelocity and acceleration both point right.

Question 18

A swimmer travels \(100\unit{m}\) at an average speed of \(2.0\unit{m/s}\). How long does the swim take?

A\(0.020\unit{s}\)B\(98\unit{s}\)C\(200\unit{s}\)D\(50\unit{s}\)

Question 19

A sensor file should show \(7.5\times10^{6}\), but a student enters \(7.5\times10^{5}\). How does the entered value compare with the intended value?

AIt is ten times as large.BIt has exactly the intended value.CIt is one tenth as large.DIt is five times as large.

Question 20

An isotope has atomic number 9 and mass number 19. How many neutrons are in its nucleus?

A10B9C19D28

Question 21

Why do astronauts inside an orbiting laboratory appear weightless?

AEarth's gravity is too weak to act at the laboratory's altitude.BThe astronauts and the laboratory fall together with nearly the same acceleration.CThe astronauts' mass becomes zero while they are in orbit.DAn outward force exactly cancels gravity everywhere inside the laboratory.

Question 22

A student tests how fan speed affects the cooling of the same warm object. Each trial begins at the same temperature. The student changes the fan speed and records the time required for the object's temperature to fall by \(10^\circ\mathrm{C}\). What is the dependent variable?

AThe time required for the temperature to fall by \(10^\circ\mathrm{C}\)BThe object's starting temperature in each trialCThe fan speed selected for each trialDThe object used in every trial

Question 23

A sled slides across a level floor and stops because of friction. Which statement best describes the principal energy transformation?

AThe sled's kinetic energy becomes mainly internal energy in the sled, floor, and nearby surroundings.BThe sled's mass becomes thermal energy as it slows.CThe sled's kinetic energy is destroyed, so total energy decreases.DThe sled's kinetic energy becomes gravitational potential energy while it remains on the level floor.

Question 24

A vehicle's velocity increases in the same direction from \(4.0\unit{m/s}\) to \(19\unit{m/s}\) with a constant acceleration of \(5.0\unit{m/s^2}\). How long does the change take?

A\(3.8\unit{s}\)B\(0.80\unit{s}\)C\(3.0\unit{s}\)D\(6.0\unit{s}\)

Question 25

A wooden block has mass \(2.1\unit{kg}\) and density \(7.0\times10^{2}\unit{kg/m^3}\). What volume does it occupy?

A\(1.5\times10^{3}\unit{m^3}\)B\(3.3\times10^{2}\unit{m^3}\)C\(0.0030\unit{m^3}\)D\(7.0\times10^{2}\unit{m^3}\)

Question 26

A buzzer sounds inside a chamber while air is removed. Why does the sound outside fade?

AThe buzzer's frequency decreases to zero as the air pressure falls.BSound requires particles that pass a mechanical disturbance from place to place.CSound keeps its normal strength, but the chamber walls block only the lower frequencies.DRemoving air makes sound travel too quickly for a listener outside to detect it.

Question 27

A \(1.0\unit{kg}\) metal sample with \(c=5.6\times10^{2}\unit{J/(kg\,K)}\) receives \(4.5\times10^{3}\unit{J}\). What temperature rise should occur?

A\(5.6\times10^{2}\unit{K}\)B\(2.5\unit{K}\)C\(16\unit{K}\)D\(8.0\unit{K}\)

Question 28

Take right as positive. A \(2.0\unit{kg}\) cart moving right at \(3.0\unit{m/s}\) receives an impulse of \(-10\unit{N\,s}\). What is its final velocity?

A\(8.0\unit{m/s}\) rightB\(2.0\unit{m/s}\) leftC\(2.0\unit{m/s}\) rightD\(5.0\unit{m/s}\) left

Question 29

An ideal jack must provide an output force of \(52\unit{N}\). Its ideal mechanical advantage is 2. What input force is required?

A\(1.0\times10^{2}\unit{N}\)B\(26\unit{N}\)C\(54\unit{N}\)D\(13\unit{N}\)

Question 30

Treat a fixed amount of gas as ideal. It is sealed in a rigid vessel, and its pressure rises from \(90\unit{kPa}\) at \(295\unit{K}\) to \(108\unit{kPa}\). What final temperature does the ideal-gas model predict, rounded to the nearest \(10\unit{K}\)?

A\(310\unit{K}\)B\(250\unit{K}\)C\(300\unit{K}\)D\(350\unit{K}\)

Question 31

A sled of mass \(6.0\unit{kg}\) experiences a \(30\unit{N}\) net force to the right. What acceleration results?

A\(5.0\unit{m/s^2}\) leftB\(24\unit{m/s^2}\) rightC\(5.0\unit{m/s^2}\) rightD\(180\unit{m/s^2}\) right

Question 32

A light ray approaches a thin converging lens parallel to its principal axis. Which path does the ideal ray follow after leaving the lens?

The incident ray is parallel to the principal axis.

AIt returns along the incident path.BIt remains parallel to the axis for every lens shape.CIt travels through the focal point on the incident side.DIt travels through the focal point on the far side.

Question 33

An atom falls from \(7.5\unit{eV}\) to \(2.75\unit{eV}\). What energy does the emitted photon carry?

A\(10\unit{eV}\)B\(4.8\unit{eV}\)C\(7.5\unit{eV}\)D\(2.8\unit{eV}\)

Question 34

In the small-angle model, the characteristic angular width of a single-slit diffraction pattern is proportional to \(\lambda/a\). The slit width changes from \(a\) to \(a/5\), and the wavelength changes from \(\lambda\) to \(2\lambda\). How does the angular width change?

Both wavelength and slit width change in the second setup.

AIt becomes approximately twice as wide.BIt becomes approximately 10 times wider.CIt becomes approximately 5 times wider.DIt becomes approximately 2.5 times wider.

Question 35

An object moving at \(6.0\unit{m/s}\) has momentum magnitude \(42\unit{kg\,m/s}\). What is its mass?

A\(250\unit{kg}\)B\(36\unit{kg}\)C\(7.0\unit{kg}\)D\(0.14\unit{kg}\)

Question 36

A calibration block is \(25.0\unit{mm}\) long. For this check, readings within \(0.2\unit{mm}\) of the reference are considered accurate, and a spread no greater than \(0.2\unit{mm}\) is considered precise. One instrument gives these readings.

Trial	1	2	3
Length (mm)	24.9	25.0	25.1

Which description fits the results?

AThey are precise but not accurate.BThey are neither accurate nor precise.CThey are accurate but not precise.DThey are both accurate and precise.

Question 37

A sensor counts 15 complete vibrations in \(3.0\unit{s}\). What frequency should it report?

A\(5.0\unit{Hz}\)B\(45\unit{Hz}\)C\(12\unit{Hz}\)D\(0.20\unit{Hz}\)

Question 38

A wave on a long spring moves at \(12\unit{m/s}\), and neighboring crests are \(2.4\unit{m}\) apart. What is its frequency?

A\(9.6\unit{Hz}\)B\(29\unit{Hz}\)C\(5.0\unit{Hz}\)D\(0.20\unit{Hz}\)

Question 39

A model predicts an output at four increasing input values. A residual is defined as measured output minus predicted output. The residuals, in input order, are \(-0.6\), \(-0.2\), \(+0.3\), and \(+0.8\). What is the clearest concern?

Residual equals measured output minus predicted output.

AThe model overpredicts the output by the same amount at every input.BThe small residual values prove that the model is exact.CThe residuals show random scatter around zero with no pattern.DThe steady drift suggests that the model misses a systematic trend.

Question 40

White light passes through an ordinary glass prism. Which visible color is usually deviated the most from its original direction after emerging from the prism?

Determine which color changes direction the most after passing through the prism.

AredBvioletCall colors by exactly the same angleDyellow

Physics for Beginners: Online Practice Test 1

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