Physics for Beginners: Online Practice Test 2

Question 1

A nonrelativistic particle's kinetic energy becomes four times as large while its mass stays the same. What fraction of its original de Broglie wavelength remains?

AThe wavelength is unchanged.BThe wavelength becomes twice as large.CThe wavelength becomes four times as large.DThe wavelength becomes half as large.

Question 2

Two carts move at the same velocity. Cart B has three times Cart A's mass. How do their momenta compare?

ATheir momenta are equal.BB has three times A's momentum.CB has nine times A's momentum.DB has one third of A's momentum.

Question 3

A tire gauge displays pressure. Which SI unit belongs on its scale?

Apascal (Pa)Bnewton (N)Cwatt (W)Dohm (\(\Omega\))

Question 4

Why can sound be heard around an open doorway even when the speaker is not visible?

AThe doorway increases the sound's frequency.BThe sound reflects only from the floor.CSound diffracts through the doorway.DThe sound speed becomes greater at the doorway.

Question 5

A cart's position is recorded once each second.

Time (s)	0	1.0	2.0	3.0
Position (m)	0	1.0	4.0	9.0

Which description is best supported by the data?

AIts interval velocity increases by \(2.0\unit{m/s}\) each second, so its acceleration is constant and positive.BIt covers \(3.0\unit{m}\) each second, so its velocity is constant and positive.CIts interval velocity decreases by \(2.0\unit{m/s}\) each second, so its acceleration is constant and negative.DIts starting position is zero, so it remains at rest during the recorded interval.

Question 6

An incoming ray makes a \(58^\circ\) angle with a mirror's surface. What is its angle of incidence?

Angles of incidence are measured from the normal.

A\(58^\circ\)B\(64^\circ\)C\(32^\circ\)D\(122^\circ\)

Question 7

The frequency of an oscillator doubles while its motion remains periodic. What happens to its period?

AThe period is halved.BThe period doubles.CThe period becomes four times as large.DThe period is unchanged.

Question 8

The same net force is applied first to mass \(m\) and then to mass \(2m\). How does the second acceleration compare with the first?

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

Question 9

A ruler marked every \(0.1\unit{cm}\) gives length readings of \(14.2\unit{cm}\), \(14.3\unit{cm}\), and \(14.4\unit{cm}\). Which summary is most defensible?

AReport a center near \(14.3\unit{cm}\) and an observed range of \(0.2\unit{cm}\).BReport exactly \(14.300000\unit{cm}\) and omit any uncertainty.CReport only the largest measurement, \(14.4\unit{cm}\).DReport no result because the measurements are not identical.

Question 10

The same perpendicular force is applied first halfway from a door's hinge to its handle and then at the handle. How does the second torque compare with the first?

Both forces are perpendicular to the door.

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

Question 11

A straight velocity-time graph rises from \(-2.0\unit{m/s}\) at \(0\unit{s}\) to \(6.0\unit{m/s}\) at \(4.0\unit{s}\). What acceleration does its slope represent?

A\(4.0\unit{m/s^2}\)B\(2.0\unit{m/s^2}\)C\(1.0\unit{m/s^2}\)D\(8.0\unit{m/s^2}\)

Question 12

Why can grounding a metal object change its net charge?

AThe grounding wire blocks electrons from entering or leaving the object.BEarth sends protons through the wire until the object's mass changes.CA conducting connection lets electrons move between the object and Earth.DThe wire creates equal positive and negative charge on the object in every case.

Question 13

A book rests on a table. Which force is the third-law partner of the book's downward push on the table?

Third-law partners act on different objects.

AThe table's downward weight.BEarth's downward gravitational pull on the book.CThe book's upward pull on Earth.DThe table's upward push on the book.

Question 14

Which change lowers external radiation exposure without changing the source itself?

ADecrease the distance while keeping the exposure time fixed.BIncrease the exposure time while keeping the distance fixed.CReplace shielding with a thinner layer of the same material.DIncrease distance from the source and reduce time nearby.

Question 15

A gas loses \(2.1\times10^{2}\unit{J}\) of internal energy while the surroundings do \(7.0\times10^{1}\unit{J}\) of work on the gas. How much energy leaves the gas by heating?

A\(2.1\times10^{2}\unit{J}\)B\(2.8\times10^{2}\unit{J}\)C\(1.4\times10^{2}\unit{J}\)D\(7.0\times10^{1}\unit{J}\)

Question 16

An object stands \(30\unit{cm}\) from a thin converging lens whose focal length is \(10\unit{cm}\). Which image description is correct?

Use the thin-lens equation, then use magnification to determine orientation and size.

AThe image is virtual, upright, and half the object's height.BThe image is real, upright, and the same height as the object.CThe image is real, inverted, and twice the object's height.DThe image is real, inverted, and half the object's height.

Question 17

A cart is pulled by the same force in every trial. A student changes the cart's total mass and measures its acceleration. Which variable is independent?

AThe motion sensorBThe pulling forceCThe measured accelerationDThe cart's total mass

Question 18

A displacement sensor records 3 complete oscillations in \(6.0\unit{s}\). What is the measured period?

A\(6.0\unit{s}\)B\(2.0\unit{s}\)C\(3.0\unit{s}\)D\(0.50\unit{s}\)

Question 19

Two safety designs bring the same moving passenger to rest. Design B spreads the momentum change over twice the time used by Design A. How does B's average force compare?

AThe average forces are equal.BB's average force is twice as large.CB's average force is four times as large.DB's average force is half as large.

Question 20

If gravity suddenly vanished from a satellite in circular orbit, what path would it initially follow?

The satellite has an instantaneous velocity when gravity disappears.

AA straight line toward the planet.BA smaller circle.CA straight line tangent to the orbit.DIt would stop instantly.

Question 21

A cart coasts up a smooth ramp with its motor off. Air drag is negligible. What happens before the cart stops momentarily?

AKinetic energy stays fixed because no motor works.BBoth energies increase.CKinetic energy decreases while gravitational potential energy increases.DGravitational potential energy decreases as height rises.

Question 22

A compass sits beside a straight wire that passes perpendicularly through a tabletop. Ignore other magnetic fields. The current reverses without changing its magnitude. What happens to the compass deflection caused by the wire?

Only the current direction changes.

AThe deflection stays in the same direction because the current magnitude is unchanged.BThe wire's magnetic field reverses direction, so the compass deflection reverses.CThe deflection becomes zero because a reversed current produces no magnetic field.DThe deflection becomes twice as large in the same direction.

Question 23

A heavy ball and a light ball are released together in a vacuum near Earth. How do their accelerations compare?

AThe heavy ball accelerates more.BNeither accelerates in a vacuum.CThe light ball accelerates more.DThey have the same downward acceleration.

Question 24

Equal masses of copper and water receive equal amounts of energy, and neither sample changes phase. Water has the larger specific heat capacity. Which sample undergoes the larger temperature change?

AThe copperBThe waterCNeither changes temperature.DThey change by the same amount.

Question 25

A wooden block floats motionless with part of its volume above water. How does the buoyant force compare with its weight?

AThe two forces are equal in magnitude.BThe buoyant force is zero at the surface.CThe weight is larger because wood has mass.DThe buoyant force is larger because the block is partly above water.

Question 26

A \(30\unit{\mu F}\) capacitor is charged to \(6.0\unit{V}\). What is the magnitude of charge on either plate?

A\(360\unit{\mu C}\)B\(5.0\unit{\mu C}\)C\(180\unit{\mu C}\)D\(36\unit{\mu C}\)

Question 27

A turntable speeds up from \(4.0\unit{rad/s}\) to \(8.0\unit{rad/s}\). What happens to the tangential speed of a fixed point on its rim?

AIt remains unchanged.BIt doubles.CIt becomes four times as large.DIt is cut in half.

Question 28

A granite cube and a foam cube have the same volume. Granite is denser than foam. Which comparison must be true?

ADensity cannot be used when volumes match.BThe granite cube has greater mass.CThe cubes must have equal mass.DThe foam cube has greater mass.

Question 29

A radio carrier has frequency \(1.0\times10^{2}\unit{MHz}\). What is its approximate wavelength in vacuum?

A\(3.0\times10^{1}\unit{m}\)B\(0.33\unit{m}\)C\(1.0\times10^{2}\unit{m}\)D\(3.0\unit{m}\)

Question 30

A report gives a count as \(60\times10^{2}\). Which expression is the same value and is written in normalized scientific notation?

A\(6.0\times10^{2}\)B\(0.60\times10^{2}\)C\(60\times10^{3}\)D\(6.0\times10^{3}\)

Question 31

An ideal gas is sealed in a rigid vessel and cools until its kelvin temperature is 90 percent of the starting value. What happens to its absolute pressure?

AThe absolute pressure becomes 0.90 times its initial value.BThe absolute pressure becomes 1.10 times its initial value.CThe absolute pressure becomes 0.10 times its initial value.DThe absolute pressure stays unchanged.

Question 32

Kinetic friction of \(12\unit{N}\) opposes a crate as it slides \(4.0\unit{m}\). What work does friction do?

A\(16\unit{J}\)B\(-3.0\unit{J}\)C\(-48\unit{J}\)D\(+48\unit{J}\)

Question 33

An ideal machine has mechanical advantage 3. If the output moves \(0.20\unit{m}\), how far must the input move?

A\(0.20\unit{m}\)B\(0.067\unit{m}\)C\(0.60\unit{m}\)D\(1.8\unit{m}\)

Question 34

An ambulance approaches a stationary listener with its siren on. How does the heard frequency compare with the emitted frequency?

AIt is zero.BThe heard frequency is higher.CIt is unchanged for every relative motion.DIt is lower.

Question 35

A detector records this background-corrected count rate.

Time (h)	0	4.0	8.0
Count rate (per min)	800	400	200

What half-life fits the data?

A\(4.0\unit{h}\)B\(2.0\unit{h}\)C\(12\unit{h}\)D\(8.0\unit{h}\)

Question 36

A wave remains in the same medium while its source frequency doubles. The wave speed is unchanged. What happens to wavelength?

AIt becomes four times as large.BIt stays unchanged.CIt doubles.DIt is halved.

Question 37

A cyclist completes one lap of a closed track in \(3.0\times10^{1}\unit{s}\) and stops at the starting line. What is the cyclist's average velocity for the lap?

AThe lap length divided by \(3.0\times10^{1}\unit{s}\)B\(3.0\times10^{1}\unit{m/s}\)C\(0\unit{m/s}\)DIt cannot be found because the cyclist moved.

Question 38

A \(6.8\times10^{2}\unit{Hz}\) tone travels through air at \(3.4\times10^{2}\unit{m/s}\). What is its wavelength?

A\(0.50\unit{m}\)B\(1.0\times10^{3}\unit{m}\)C\(3.4\times10^{2}\unit{m}\)D\(2.0\unit{m}\)

Question 39

A bar magnet rests motionless inside a stationary coil. What steady induced emf is expected?

AA maximum emf because the field is strong.BAn emf that grows with time.CZero, because the magnetic flux is not changing.DA constant emf set only by magnet mass.

Question 40

A person walks \(120\unit{m}\) in \(80\unit{s}\), then \(60\unit{m}\) in \(40\unit{s}\). What is the average speed for the whole walk?

A\(0.67\unit{m/s}\)B\(1.5\unit{m/s}\)C\(2.3\unit{m/s}\)D\(3.0\unit{m/s}\)

Physics for Beginners: Online Practice Test 2

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