OCR GCE AS Level Physics A AS Paper 2 June 2023 question paper H156/02

The brakes of a car of mass 1200 kg are being tested on a track. The driver sees a hazard and applies the brakes.

The graph shows the variation of the velocity v of the car with time t from when the driver sees the hazard to when the car stops.

Calculate the acceleration a of the car while the brakes are applied.

=........ m s^–2 a

Calculate the average braking force F while the brakes are applied.

Calculate the total stopping distance d of the car.

Calculate the work W done by the brakes to stop the car.

The same driver in the same car repeats the test at half the initial velocity. The braking force is constant.

On the graph, draw the variation of velocity of the car from the time the driver sees the

hazard to the time the car stops.

Explain how your graph in (b) would change if:

the driver was tired

the surface of the track was more resistive.

2* A student is investigating the motion of small metal balls falling from rest vertically through a liquid.

The student drops a ball of diameter d from rest at the surface of the liquid. The student determines the terminal velocity v of the ball in the liquid.

It is suggested that the relationship between the terminal velocity v and the diameter d is

where is the density of the metal is the density of the liquid g is the acceleration of free fall = 9.81 ms^–2 and K is a constant.

Describe, with the aid of a suitable diagram:

• how an experiment can be safely conducted to test this relationship between v and d, and

• how the data can be analysed to determine K.

Diagram

A student throws a ball of mass 0.210 kg. The hand of the student is a vertical distance of 2.40 m above the ground. The ball leaves the student’s hand with a velocity of 22.3 m s^–1 at an angle of 84.0° to the vertical as shown in the diagram.

Assume that air resistance is negligible.

Show that the vertical component u_v of the velocity of the ball as it leaves the student’s hand is about 2.33 m s^–1.

Show that the vertical component v_v of the velocity of the ball as it hits the ground is about 7.25 m s^–1.

Calculate the kinetic energy E_k of the ball as it hits the ground.

Explain why the momentum of the ball changes as the ball travels from the hand to the ground.

Two identical springs each have a force constant of 36 N m^–1. In an experiment, the two 4 (a) springs are suspended from a fixed support as shown in Fig. 4.1.

The new length of the spring arrangement is L.

State the name of the instrument the student used to measure L₀ and L.

Determine the extension x of the spring arrangement. Include the absolute uncertainty in your answer.

x =........ ±........ mm

Calculate the mass M of the object. Write your answer to 2 significant figures.

Calculate the total energy W stored by the springs when the object is suspended.

A metal wire has a length of 4.4 m. The Young modulus of the metal is 120 GPa.

In an experiment force is applied to the wire and the extension is measured. The graph shows the variation of the extension of the wire with the force applied.

The gradient of the linear section of the graph is 1.6 N mm^–1. (i)

Determine the cross-sectional area A of the wire.

Use the graph to determine an estimate of the work done E_w in stretching the wire when a 3.5 N force is applied.

Two spherical dippers, D1 and D2 oscillate on a ripple tank as shown in Fig. 5.1.

Waves on the surface of the water are produced from each dipper. These waves are in phase with each other.

The water waves have a speed of 8.0 cm s^–1 and a wavelength of 3.2 cm.

State and explain whether these waves are transverse or longitudinal waves.

State and explain whether these waves are plane polarised.

Calculate the frequency f of the dippers.

The distance between P and D1 is 12.2 cm. The distance between P and D2 is 20.2 cm.

Explain whether constructive or destructive interference occurs at P.

A switch, resistor of resistance R and a component Z are connected to a battery of electromotive force (e.m.f.) E and internal resistance r. An ammeter and voltmeter are also connected to the circuit as shown in Fig. 6.1.

Fig. 6.2 shows the current I and potential difference V characteristic for the electrical component Z.

State the name of component Z.

The switch is initially open.

The voltmeter reading is 5.72 V

The following voltmeters are available:

A: 0–2 V, ± 0.001 V B: 0–2 V, ± 0.01 V C: 0–2 V, ± 0.1 V

D: 0–20 V, ± 0.001 V E: 0–20 V, ± 0.01 V F: 0–20 V, ± 0.1 V

State the voltmeter, A to F, that has been used in this experiment.

The switch is now closed.

The ammeter and voltmeter readings are:

Ammeter reading = 220 mA

Voltmeter reading = 4.80 V

Show that the resistance of R is 120 .

Determine values for E and r.

The resistor R is changed to a lower value.

State and explain the change, if any, in the ammeter and voltmeter readings when the switch is closed.

Electromagnetic radiation is incident on a metal plate. Photoelectrons are emitted.

State why electrons are emitted.

The metal plate has a threshold frequency of 990 THz.

State what is meant by the term threshold frequency.

The maximum kinetic energy of the emitted photoelectrons is 1.9 eV.

Show that the maximum kinetic energy of the emitted photoelectrons, is about 3.0 10^–19 J.

Determine the wavelength of the incident electromagnetic radiation.

The intensity of the incident radiation is doubled.

State the change, if any, on

the maximum kinetic energy of the photoelectrons emitted from the surface of the metal plate

the rate of emission of the photoelectrons.