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Gaokao Physics study materials
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Gaokao Physics practice questions

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Question 1Mechanics

A cart starts from rest and moves with constant acceleration 2.5 m/s^2 for 4 s. What is its speed at the end of the interval?

  1. 2.5 m/s
  2. 6.5 m/s
  3. 10 m/s Correct answer.
  4. 16 m/s

Explanation

For constant acceleration from rest, v = at. With a = 2.5 m/s^2 and t = 4 s, v = 10 m/s.

Question 2Mechanics

A velocity-time graph is a straight line from v = 0 m/s at t = 0 to v = 6 m/s at t = 3 s. What displacement is represented?

  1. 6 m
  2. 9 m Correct answer.
  3. 12 m
  4. 18 m

Explanation

Displacement is the area under the velocity-time graph. The triangular area is (1/2)(3 s)(6 m/s) = 9 m.

Question 3Mechanics

A 4 kg object is acted on by a net force of 12 N. What is its acceleration?

  1. 2 m/s^2
  2. 3 m/s^2 Correct answer.
  3. 12 m/s^2
  4. 48 m/s^2

Explanation

Newton's second law gives a = F/m. The acceleration is 12 N / 4 kg = 3 m/s^2.

Question 4Mechanics

A book rests on a car seat while the car accelerates forward. If the book does not slip, what is the direction of static friction on the book?

  1. Forward Correct answer.
  2. Backward
  3. Vertically upward
  4. Zero, because the book is at rest relative to the seat

Explanation

The book needs a forward horizontal force to accelerate with the car. Static friction from the seat provides that forward force.

Question 5Mechanics

How much work is done against gravity when a 5 kg mass is lifted vertically by 2 m? Use g = 10 m/s^2.

  1. 10 J
  2. 25 J
  3. 50 J
  4. 100 J Correct answer.

Explanation

The work done against gravity equals mgh. With m = 5 kg, g = 10 m/s^2, and h = 2 m, W = 100 J.

Question 6Mechanics

If the speed of a moving object is doubled while its mass stays the same, what happens to its kinetic energy?

  1. It doubles
  2. It triples
  3. It becomes four times as large Correct answer.
  4. It is unchanged

Explanation

Kinetic energy is (1/2)mv^2, so it depends on the square of speed. Doubling v makes v^2 four times larger.

Question 7Mechanics

Two identical carts move on a frictionless track. One cart with speed v collides with a stationary cart and they stick together. What is their final speed?

  1. v/4
  2. v/2 Correct answer.
  3. v
  4. 2v

Explanation

Momentum is conserved. The initial momentum mv becomes (2m)V after sticking, so V = v/2.

Question 8Mechanics

A ball is launched horizontally from a table. Neglecting air resistance, which quantity remains constant during the flight?

  1. Horizontal velocity Correct answer.
  2. Vertical velocity
  3. Total speed
  4. Gravitational potential energy

Explanation

With no air resistance, there is no horizontal force, so horizontal velocity stays constant. Gravity changes only the vertical component.

Question 9Mechanics

An object moves in a circle of radius r with speed v. What is the magnitude of its centripetal acceleration?

  1. vr
  2. v/r
  3. v^2/r Correct answer.
  4. r/v^2

Explanation

Uniform circular motion has centripetal acceleration a = v^2/r toward the center. The direction changes even when the speed is constant.

Question 10Mechanics

A spring with k = 200 N/m is compressed by 0.10 m. What elastic potential energy is stored?

  1. 0.5 J
  2. 1.0 J Correct answer.
  3. 2.0 J
  4. 20 J

Explanation

Spring energy is (1/2)kx^2. Substituting k = 200 N/m and x = 0.10 m gives 1.0 J.

Question 11Mechanics

If the distance between two point masses is doubled, how does the gravitational force between them change?

  1. It becomes one-fourth as large Correct answer.
  2. It becomes one-half as large
  3. It doubles
  4. It becomes four times as large

Explanation

Newton's law of gravitation has F proportional to 1/r^2. Doubling r makes the force 1/2^2 = 1/4 as large.

Question 12Mechanics

Two perpendicular forces of 6 N and 8 N act on the same point. What is the magnitude of their resultant?

  1. 2 N
  2. 10 N Correct answer.
  3. 14 N
  4. 48 N

Explanation

For perpendicular vectors, use the Pythagorean theorem. The resultant is sqrt(6^2 + 8^2) = 10 N.

Question 13Mechanics

A car moving at 20 m/s brakes uniformly to rest with acceleration magnitude 5 m/s^2. What braking distance is required?

  1. 20 m
  2. 40 m Correct answer.
  3. 60 m
  4. 80 m

Explanation

Use v^2 = v0^2 + 2as with final speed zero. The distance is v0^2/(2a) = 400/(10) = 40 m.

Question 14Mechanics

A 3 kg block on a frictionless table is connected over a light pulley to a hanging 1 kg mass. Use g = 10 m/s^2. What is the acceleration of the system?

  1. 1.0 m/s^2
  2. 2.5 m/s^2 Correct answer.
  3. 3.3 m/s^2
  4. 10 m/s^2

Explanation

The external driving force on the two-mass system is the hanging weight, 10 N. The total mass is 4 kg, so a = 10/4 = 2.5 m/s^2.

Question 15Mechanics

A block slides down a frictionless 30 degree incline. What is its acceleration along the incline? Use g = 10 m/s^2.

  1. 2.5 m/s^2
  2. 5.0 m/s^2 Correct answer.
  3. 8.7 m/s^2
  4. 10 m/s^2

Explanation

The component of gravity along the incline is g sin theta. With theta = 30 degrees, a = 10 x 0.5 = 5.0 m/s^2.

Question 16Mechanics

A 0.20 kg block moving at 4.0 m/s compresses a spring of k = 400 N/m on a frictionless surface. What is the maximum compression?

  1. 4.5 cm
  2. 6.3 cm
  3. 8.9 cm Correct answer.
  4. 16 cm

Explanation

At maximum compression, initial kinetic energy becomes spring energy. (1/2)(0.20)(4.0^2) = (1/2)(400)x^2, so x = sqrt(0.008) = 0.089 m.

Question 17Mechanics

Two projectiles are launched from level ground with the same speed at angles 30 degrees and 60 degrees. Neglect air resistance. How do their ranges compare?

  1. The 30 degree range is larger
  2. The 60 degree range is larger
  3. The ranges are equal Correct answer.
  4. The comparison depends on mass

Explanation

Range for level-ground projectile motion is R = v0^2 sin(2theta)/g. Since sin 60 degrees equals sin 120 degrees, the 30 degree and 60 degree ranges are equal.

Question 18Mechanics

A small object moves uniformly in a circle of radius 0.50 m with period 1.0 s. What is its centripetal acceleration?

  1. pi^2 m/s^2
  2. 2pi^2 m/s^2 Correct answer.
  3. 4pi^2 m/s^2
  4. 8pi^2 m/s^2

Explanation

For period T, a = 4pi^2r/T^2. With r = 0.50 m and T = 1.0 s, a = 2pi^2 m/s^2.

Question 19Mechanics

In a perfectly elastic head-on collision between two identical carts, cart A initially moves with speed v and cart B is initially at rest. What happens after the collision?

  1. Cart A stops and cart B moves with speed v Correct answer.
  2. Both carts move together at speed v/2
  3. Cart A rebounds with speed v and cart B remains at rest
  4. Both carts move in opposite directions with speed v

Explanation

For a one-dimensional elastic collision of identical masses, the carts exchange velocities. The initially moving cart stops, and the initially stationary cart moves with speed v.

Question 20Mechanics

A satellite moves in a circular orbit around Earth. If the orbital radius becomes four times larger, how does the orbital speed change?

  1. It becomes one-fourth as large
  2. It becomes one-half as large Correct answer.
  3. It doubles
  4. It becomes four times as large

Explanation

For a circular orbit, v = sqrt(GM/r). Increasing r by a factor of 4 reduces v by sqrt(4) = 2, so the speed becomes one-half as large.

Question 21Mechanics

In simple harmonic motion with amplitude A, what fraction of the total mechanical energy is kinetic energy when the displacement is A/2?

  1. 1/4
  2. 1/2
  3. 3/4 Correct answer.
  4. 1

Explanation

Total energy is (1/2)kA^2, and potential energy at x = A/2 is (1/2)k(A/2)^2 = one-fourth of total. The kinetic fraction is therefore 1 - 1/4 = 3/4.

Question 22Mechanics

A block floats at rest in water. Which statement about the buoyant force on the block is correct?

  1. It is greater than the block's weight
  2. It is equal to the block's weight Correct answer.
  3. It is less than the block's weight
  4. It is zero because the block is not moving

Explanation

For a floating object at rest, vertical forces balance. The buoyant force equals the object's weight.

Question 23Mechanics

A uniform 4 m beam of weight 100 N is hinged at one end and supported vertically at the other end. What upward support force is needed at the far end?

  1. 25 N
  2. 50 N Correct answer.
  3. 100 N
  4. 200 N

Explanation

Taking torques about the hinge, the beam's weight acts at its center, 2 m from the hinge. The support force F at 4 m satisfies F(4) = 100(2), so F = 50 N.

Question 24Mechanics

A boat points directly across a 100 m wide river and moves at 5 m/s relative to the water. The current is 3 m/s downstream. How long does the boat take to cross?

  1. 12.5 s
  2. 20 s Correct answer.
  3. 25 s
  4. 33 s

Explanation

The crossing time depends on the velocity component perpendicular to the bank, which is 5 m/s. Time = 100 m / 5 m/s = 20 s.

Question 25Mechanics

On a position-time graph, what does the slope of the tangent at a point represent?

  1. Instantaneous velocity Correct answer.
  2. Instantaneous acceleration
  3. Net force
  4. Kinetic energy

Explanation

The slope of a position-time graph is dx/dt, which is instantaneous velocity. Acceleration is the slope of a velocity-time graph.

Question 26Mechanics

A system initially at rest explodes into two fragments. A 2 kg fragment moves east at 6 m/s. What is the velocity of the 3 kg fragment?

  1. 4 m/s east
  2. 4 m/s west Correct answer.
  3. 9 m/s east
  4. 9 m/s west

Explanation

Initial momentum is zero, so final momenta must cancel. The 2 kg fragment has 12 kg m/s east, so the 3 kg fragment must have 12 kg m/s west, giving speed 4 m/s west.

Question 27Mechanics

A ball is launched horizontally at 15 m/s from a height of 20 m. Use g = 10 m/s^2 and neglect air resistance. What is its speed just before hitting the ground?

  1. 15 m/s
  2. 20 m/s
  3. 25 m/s Correct answer.
  4. 35 m/s

Explanation

The fall time satisfies 20 = (1/2)gt^2, so t = 2 s and vertical speed is 20 m/s. The horizontal component remains 15 m/s, so the final speed is sqrt(15^2 + 20^2) = 25 m/s.

Question 28Mechanics

A block slides down a 30 degree incline with kinetic friction coefficient 0.20. Use g = 10 m/s^2 and cos 30 degrees = 0.866. What is its acceleration down the plane?

  1. 1.73 m/s^2
  2. 3.27 m/s^2 Correct answer.
  3. 5.00 m/s^2
  4. 6.73 m/s^2

Explanation

The acceleration is g(sin theta - mu cos theta). With sin 30 degrees = 0.5, a = 10(0.5 - 0.20 x 0.866) = 3.27 m/s^2.

Question 29Mechanics

A 2 kg block on a frictionless table is connected to a hanging 1 kg mass. Starting from rest, the hanging mass descends 1.0 m. Use g = 10 m/s^2. What is the speed of the system then?

  1. 1.8 m/s
  2. 2.6 m/s Correct answer.
  3. 3.2 m/s
  4. 4.5 m/s

Explanation

The lost gravitational potential energy is 1 x 10 x 1 = 10 J. It becomes kinetic energy of 3 kg total mass: 10 = (1/2)(3)v^2, so v = sqrt(20/3) = 2.6 m/s.

Question 30Mechanics

A 1 kg cart moving at 8 m/s sticks to a 3 kg cart attached to a spring of k = 400 N/m. After the collision, the combined carts compress the spring. What is the maximum compression?

  1. 0.10 m
  2. 0.20 m Correct answer.
  3. 0.40 m
  4. 0.80 m

Explanation

Momentum gives the post-collision speed: (1)(8) = (4)V, so V = 2 m/s. The kinetic energy after collision is (1/2)(4)(2^2) = 8 J, so (1/2)(400)x^2 = 8 and x = 0.20 m.

Question 31Mechanics

A small mass on a string must complete a vertical circle of radius 0.80 m. What minimum speed is needed at the bottom? Use g = 10 m/s^2.

  1. 2.8 m/s
  2. 4.0 m/s
  3. 6.3 m/s Correct answer.
  4. 8.0 m/s

Explanation

At the top, the minimum speed satisfies v_top^2 = gR. Energy from bottom to top gives (1/2)v_bottom^2 = (1/2)gR + 2gR, so v_bottom = sqrt(5gR) = sqrt(40) = 6.3 m/s.

Question 32Mechanics

A solid cylinder rolls without slipping down a height of 1.2 m from rest. Use I = (1/2)mR^2 and g = 10 m/s^2. What is its center-of-mass speed at the bottom?

  1. 2.8 m/s
  2. 4.0 m/s Correct answer.
  3. 4.9 m/s
  4. 6.0 m/s

Explanation

Energy gives mgh = (1/2)mv^2 + (1/2)I(v/R)^2 = (1/2)mv^2 + (1/4)mv^2 = (3/4)mv^2. Thus v = sqrt(4gh/3) = sqrt(16) = 4.0 m/s.

Question 33Electricity Magnetism

A 6 ohm resistor is connected across a 18 V battery. What current flows through the resistor?

  1. 0.33 A
  2. 3 A Correct answer.
  3. 12 A
  4. 108 A

Explanation

Ohm's law gives I = V/R. The current is 18 V / 6 ohm = 3 A.

Question 34Electricity Magnetism

Resistors of 5 ohm and 7 ohm are connected in series. What is the equivalent resistance?

  1. 2 ohm
  2. 2.9 ohm
  3. 12 ohm Correct answer.
  4. 35 ohm

Explanation

Series resistances add directly. The equivalent resistance is 5 ohm + 7 ohm = 12 ohm.

Question 35Electricity Magnetism

A 6 ohm resistor and a 3 ohm resistor are connected in parallel. What is the equivalent resistance?

  1. 1 ohm
  2. 2 ohm Correct answer.
  3. 4.5 ohm
  4. 9 ohm

Explanation

For parallel resistors, 1/R = 1/6 + 1/3 = 1/2, so R = 2 ohm. The equivalent is less than the smallest branch resistance.

Question 36Electricity Magnetism

An appliance operates at 12 V and draws 5 A. What is its electric power?

  1. 2.4 W
  2. 17 W
  3. 60 W Correct answer.
  4. 120 W

Explanation

Electric power is P = VI. With V = 12 V and I = 5 A, P = 60 W.

Question 37Electricity Magnetism

A positive test charge is placed in a uniform electric field directed to the right. What is the direction of the electric force on it?

  1. To the right Correct answer.
  2. To the left
  3. Upward
  4. Zero

Explanation

The electric field direction is defined as the force direction on a positive test charge. Therefore the force is to the right.

Question 38Electricity Magnetism

A 2 microfarad capacitor is connected to a 12 V source. What charge is stored on one plate?

  1. 6 microC
  2. 12 microC
  3. 24 microC Correct answer.
  4. 48 microC

Explanation

Capacitor charge is Q = CV. With C = 2 microfarad and V = 12 V, Q = 24 microC.

Question 39Electricity Magnetism

A straight wire carries current east in a magnetic field directed north. What is the direction of the magnetic force on the wire?

  1. Upward Correct answer.
  2. Downward
  3. East
  4. West

Explanation

For a current-carrying wire, the force direction follows I cross B. East cross north points upward.

Question 40Electricity Magnetism

The magnetic flux through a coil changes uniformly from 0.06 Wb to 0.02 Wb in 0.10 s. What is the magnitude of the induced emf in a one-turn coil?

  1. 0.04 V
  2. 0.4 V Correct answer.
  3. 0.8 V
  4. 4 V

Explanation

The magnitude of induced emf is |delta flux|/delta t. The flux change is 0.04 Wb, so emf = 0.04/0.10 = 0.4 V.

Question 41Electricity Magnetism

An ideal transformer has 200 turns on the primary coil and 50 turns on the secondary coil. If the primary voltage is 220 V, what is the secondary voltage?

  1. 55 V Correct answer.
  2. 110 V
  3. 440 V
  4. 880 V

Explanation

For an ideal transformer, Vs/Vp = Ns/Np. Thus Vs = 220 x 50/200 = 55 V.

Question 42Electricity Magnetism

A positive charge of 2 C moves from a point at 10 V to a point at 5 V. How much work does the electric field do?

  1. -10 J
  2. -5 J
  3. 5 J
  4. 10 J Correct answer.

Explanation

The electric potential energy change is q(Vf - Vi) = 2(5 - 10) = -10 J. Work done by the electric field is the negative of that change, so it is +10 J.

Question 43Electricity Magnetism

At the midpoint between equal charges +Q and -Q, what is the direction of the electric field?

  1. Toward the +Q charge
  2. Toward the -Q charge Correct answer.
  3. Perpendicular to the line joining the charges
  4. Zero because the charges have equal magnitude

Explanation

At the midpoint, the field from +Q points away from +Q, and the field from -Q points toward -Q. Both directions are toward the negative charge, so they add.

Question 44Electricity Magnetism

A battery has emf 12 V and internal resistance 1 ohm. It supplies an external 5 ohm resistor. What is the terminal voltage?

  1. 2 V
  2. 10 V Correct answer.
  3. 12 V
  4. 14 V

Explanation

The total resistance is 6 ohm, so the current is 12/6 = 2 A. Terminal voltage across the external resistor is IR = 2 x 5 = 10 V.

Question 45Electricity Magnetism

In a Wheatstone bridge, the four arm resistances are 2 ohm, 4 ohm, 3 ohm, and 6 ohm in matching ratio. What is the current through the galvanometer branch?

  1. Zero Correct answer.
  2. One-half of the battery current
  3. The same as the current in the 2 ohm arm
  4. It depends only on the battery voltage

Explanation

The bridge is balanced because 2/4 = 3/6. The two midpoint potentials are equal, so no current flows through the galvanometer.

Question 46Electricity Magnetism

A 4 microfarad capacitor is charged to 10 V. What energy is stored in it?

  1. 20 microJ
  2. 100 microJ
  3. 200 microJ Correct answer.
  4. 400 microJ

Explanation

Capacitor energy is (1/2)CV^2. With C = 4 microfarad and V = 10 V, U = 0.5 x 4 microfarad x 100 = 200 microJ.

Question 47Electricity Magnetism

How should an ideal voltmeter be connected to measure the voltage across a resistor?

  1. In series with the resistor
  2. In parallel with the resistor Correct answer.
  3. In place of the battery
  4. Between two points of the same wire segment

Explanation

A voltmeter measures potential difference between two points, so it is connected in parallel with the component. An ideal voltmeter has very large resistance and draws negligible current.

Question 48Electricity Magnetism

A charge of 2.0 x 10^-6 C moves perpendicular to a 0.50 T magnetic field at 3.0 x 10^4 m/s. What magnetic force acts on it?

  1. 0.003 N
  2. 0.03 N Correct answer.
  3. 0.30 N
  4. 30 N

Explanation

For perpendicular motion, F = qvB. The force is (2.0 x 10^-6)(3.0 x 10^4)(0.50) = 0.03 N.

Question 49Electricity Magnetism

In a velocity selector, the electric field is 2000 N/C and the magnetic field is 0.50 T. What particle speed passes undeflected?

  1. 1000 m/s
  2. 2000 m/s
  3. 4000 m/s Correct answer.
  4. 8000 m/s

Explanation

For no deflection, qE = qvB, so v = E/B. Thus v = 2000/0.50 = 4000 m/s.

Question 50Electricity Magnetism

The north pole of a magnet approaches a conducting loop along its axis. What magnetic face does the near side of the loop tend to become?

  1. North, to oppose the approach Correct answer.
  2. South, to attract the magnet more strongly
  3. Neither; no current is induced
  4. It alternates north and south each instant

Explanation

By Lenz's law, the induced current opposes the increase in magnetic flux. The near side becomes a north face to repel the approaching north pole.