Practice Paper 2 (HL IB Physics)

Two blocks of mass 4.5 kg and 6.0 kg are joined by a string and rest on a smooth horizontal table. A force F of 100 N is applied to one of the blocks. 

Calculate

The 4.5 kg block is now placed on top of the 6.0 kg block. The coeffecient of static friction between them is 0.40. 

Calculate the maximum horizontal force F that can be applied to the bottom block that would result in both blocks moving together without slipping. 

The two blocks are now attached by a light inextensible string that passes over a smooth pulley. They are held stationary and suddenly released. 

Determine the acceleration of each block and the tension in the string.  

A motor is used to lift a 50 kg mass from rest up a vertical distance of 18 m in 0.3 minutes.

Calculate the minimum power requires to the lift the mass.

Explain why the power calculated in (a) is a minimum value.

The spectrum of radiation emitted by a sample of glacier ice is examined. The peak frequency of radiation emitted by the ice is 2.25 × 10¹³ Hz.

Calculate the temperature of the ice in °C.

The average albedo of fresh snow is 0.9. The average albedo of the glacier ice is 0.25.

The average intensity of radiation incident on the glacier is expected to change due to global warming.

When the snow melts, it exposes the glacier ice beneath the surface. 

Explain how the loss of snow could contribute to global warming.

An engineer is performing tests on a sample of helium gas (He).

Explain how the pV diagram shows that the internal energy changes during the adiabatic process from A to B.

The grey dashed lines represent isotherms.

In the diagram in part (a), point B has coordinates (300 kPa, 0.065 m³).

Calculate the number of moles of gas in the system.

The volume at point A in the adiabatic process is 0.083 m³.

Calculate the pressure at point A.

Explain why the calculation in part (c) would not be valid if the gas was water vapour.

A metal pendulum bob of mass 7.5 g is suspended from a fixed point by a length of thread with negligible mass. The pendulum is set in motion and oscillates with simple harmonic motion. 

The graph shows the kinetic energy of the bob as a function of time.

Calculate the length of the thread.

For the simple pendulum:

Show that the amplitude of the oscillation is around 0.6 m.

An experiment is set up where white light is incident on a single slit. 

The white light illuminates the slit. The first diffraction minimum for a wavelength of 630 nm is observed at 12°.  

[2]

Explain why the central maximum is white but the first secondary maximum at 12° is coloured.

In a comparison of two stars, A and B, the following data was collected

Surface temperature of star A = 25 000 K

Surface temperature of star B = 4300 K

The radius of star B was determined to be 1.1 × 10⁵ times larger than the radius of star A.

Determine the wavelengths of light for which the maximum rate of emission occurs from stars A and B.

The graph shows the variation of rate of emission against wavelength for the Sun.

On the graph, sketch the variation of rate of emission against wavelength for stars A and B.

Under the right conditions, four hydrogen nuclei can fuse to make a helium nucleus in a process known as the proton–proton cycle.    

Nuclei	Mass/ u
	1.0078
	4.0026

Show that 4 × 10^–12 J of energy is released as a result of the fusion of four hydrogen nuclei.

Fusion occurs naturally in the core of stars.

Explain why very high densities of matter and very high temperatures are needed to bring about and maintain nuclear fusion in stars.

While on the main sequence, the Sun maintains a constant luminosity of 3.86 × 10²⁶ W. It is predicted that the Sun will spend a total of 10¹⁰ years in this phase of its evolutionary cycle. 

Show that the Sun will convert a total mass of 2 × 10²⁹ kg of hydrogen into helium during its time on the main sequence. 

One day, the Sun will leave the main sequence and move on to the next stage of its evolutionary cycle.

Discuss what will happen to the Sun.

In your answer, you should outline

• the conditions that will initiate this change
• the nuclear processes that will occur 
• the physical changes that the Sun will undergo.

The gravitational field strength on the Moon's surface is 1.63 N kg^–1. It has a diameter of 3480 km.  

A rocket of mass 2 × 10⁶ kg travels from the Earth to the Moon. The first fuel tank burns enough propellant to provide thrust for the first 124 seconds and allows the rocket to accelerate from launch at a constant rate of 5.25 m s^–2.

The mass of the Earth is 5.97 × 10²⁴ kg and the mean radius is 6370 km.

In reality, less work is required to move the rocket away from the Earth's gravitational field than the value calculated in part (a).

The distance between the centre of the Earth and the centre of the Moon is 385 000 km. At a point along the rocket's journey, there is a point where the resultant gravitational field strength is zero.

Calculate the distance from the Earth where there is no resultant gravitational field strength acting on the rocket.

The gravitational field strength lines between the Earth and the Moon can be represented as shown in the diagram.

Point P is the neutral point between the Earth and the Moon where there is no resultant gravitational field.

Sketch the equipotential lines between the Earth and the Moon.

Calculate the gravitational potential at the surface of the Moon in terms of the gravitational potential on the surface of the Earth.