MaterialsEdexcel A-Level Physics: Topic test

20 questions, 54 marks

Edexcel A-Level Physics

Materials topic test

Total 54 marks

Name

Class

Date

1
An iceberg of total volume 5.0 × 10⁴ m³ floats in seawater of density 1030 kg m⁻³. The density of the ice is 920 kg m⁻³. Take g = 9.81 N kg⁻¹.
(a)
What is the mass of the iceberg?
[1 mark]
A5.2 × 10⁷ kg
B4.6 × 10⁷ kg
C54 kg
D4.5 × 10⁸ kg
(b)
What is the upthrust on the iceberg?
[1 mark]
A4.6 × 10⁷ N
B5.1 × 10⁸ N
C5.2 × 10⁷ N
D4.5 × 10⁸ N
(c)
Calculate the volume of the iceberg that is above the surface of the sea.
[2 marks]
Total for question 1: 4 marks
2
A tiny spherical water droplet of radius 1.5 × 10⁻⁵ m falls through still air at its terminal velocity of 0.027 m s⁻¹. The viscosity of air is 1.8 × 10⁻⁵ Pa s. The flow of air round the droplet is laminar.
(a)
What is the viscous drag force on the droplet?
[1 mark]
A1.4 × 10⁻¹⁰ N
B2.7 × 10⁻¹⁰ N
C7.3 × 10⁻¹² N
D4.4 × 10⁻¹¹ N
(b)
The droplet grows to twice the radius and falls in the same air at its new terminal velocity. Stokes' law still applies. By what factor does the terminal velocity increase?
[1 mark]
A2
B8
C4
D½
(c)
State two conditions that must be satisfied for Stokes' law to apply to a sphere moving through a fluid.
[2 marks]
Total for question 2: 4 marks
3
A toy dart gun contains a spring of stiffness 400 N m⁻¹ that obeys Hooke's law. The spring is compressed by 0.050 m before a dart of mass 12 g is released.
(a)
Calculate the force needed to compress the spring by 0.050 m and the elastic energy stored in it.
[3 marks]
(b)
The dart leaves the gun at 7.5 m s⁻¹. Calculate the speed it would have if all the stored energy became kinetic energy, and the efficiency of the energy transfer.
[4 marks]
Total for question 3: 7 marks
4
A steel suspension rod on a footbridge has length 4.0 m and cross-sectional area 6.0 × 10⁻⁴ m². The Young modulus of the steel is 2.1 × 10¹¹ Pa. Its limit of proportionality is at a stress of 2.5 × 10⁸ Pa, its elastic limit is at 2.6 × 10⁸ Pa and its breaking stress is 4.5 × 10⁸ Pa. The rod normally carries a tension of 1.2 × 10⁵ N.
(a)
Calculate the stress, strain and extension of the rod under its normal tension, the elastic energy stored in it, and evaluate how close the rod is to breaking.
[6 marks]
(b)
In an overload the tension rises to 2.4 × 10⁵ N. Evaluate what happens to the rod, with reference to Hooke's law, to what happens when the load is removed, and to the energy stored.
[6 marks]
Total for question 4: 12 marks
5
A concrete pillar has a square cross-section of side 0.30 m and a height of 3.0 m. It supports a compressive load of 4.5 × 10⁵ N. The Young modulus of the concrete is 2.5 × 10¹⁰ Pa and the pillar is within its elastic region.
(a)
What is the compressive stress in the pillar?
[1 mark]
A1.5 × 10⁶ Pa
B5.0 × 10⁵ Pa
C5.0 × 10⁶ Pa
D4.1 × 10⁴ Pa
(b)
What is the strain in the pillar?
[1 mark]
A2.0 × 10⁻⁴
B5.0 × 10³
C2.0 × 10⁻²
D6.0 × 10⁻⁴
(c)
Calculate the decrease in height of the pillar.
[2 marks]
Total for question 5: 4 marks
6
A hot-air balloon has an envelope of volume 2.8 × 10³ m³. The density of the surrounding air is 1.20 kg m⁻³ and the density of the hot air inside the envelope is 0.95 kg m⁻³. The structure and payload have a total mass of 400 kg. Take g = 9.81 N kg⁻¹.
(a)
What is the upthrust on the balloon?
[1 mark]
A3.4 × 10³ N
B2.6 × 10⁴ N
C3.9 × 10³ N
D3.3 × 10⁴ N
(b)
What is the resultant upward force on the balloon, including the weight of the hot air?
[1 mark]
A3.3 × 10⁴ N
B2.9 × 10³ N
C6.9 × 10³ N
D6.3 × 10⁴ N
(c)
Calculate the initial upward acceleration of the balloon.
[2 marks]
Total for question 6: 4 marks
7
A rubber cord is used to launch a model glider. As the cord is stretched, the tension is measured at several extensions: 0 N at 0 cm, 6.0 N at 10 cm, 10 N at 20 cm, 14 N at 30 cm and 20 N at 40 cm. The tension is not proportional to the extension.
(a)
Estimate the elastic energy stored in the cord when it is stretched by 40 cm.
[3 marks]
(b)
The glider has mass 0.25 kg. 75% of the stored energy becomes the kinetic energy of the glider. Calculate its launch speed and the greatest height it could reach if it were launched vertically and air resistance is ignored.
[4 marks]
Total for question 7: 7 marks
8
In an experiment on viscosity, a glass bead of radius 1.2 mm ± 0.03 mm and density 2500 kg m⁻³ is released at the top of a tall column of oil of density 920 kg m⁻³. The bead reaches terminal velocity, then takes 5.0 s ± 0.1 s to fall a distance of 0.50 m, which is measured with negligible uncertainty. Take g = 9.81 N kg⁻¹. The volume of a sphere is 4πr³/3.
(a)
Explain why the bead reaches a terminal velocity, and calculate the viscosity of the oil.
[6 marks]
(b)
Calculate the percentage uncertainty in the viscosity, and explain how the measured terminal velocity would change if the experiment were repeated with warmer oil.
[6 marks]
Total for question 8: 12 marks

End of questions

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).