3 marksExplain what is meant by a physical quantity.
2 marksState two possible physical quantities represented by the greek letter rho (ρ).
3 marksState three possible physical quantities represented by the capital letter P or the lower case letter p.
2 marksExplain how the quantities represented by P or ρ can be distinguished from each other.
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3 marksOn Fig. 1.1, draw a line from each quantity to its correct unit.
Fig. 1.1
3 marksDetermine suitable measuring units for the following quantities.
5 marksEstimate the work done by the average human in lifting a normal dining room chair off the ground, so the forearms of the person lifting are parallel with the floor at the end of the lift.
4 marksEstimate the orders of magnitude of the objects in Fig. 1.2 using the units provided.
|
Quantity |
Order of magnitude |
|
Mass of a car |
kg |
|
Thickness of a sheet of paper |
mm |
|
Density of air (at room temperature and pressure) |
kg m−3 |
|
Time between two heart beats |
s |
Fig. 1.2
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3 marksA student has a problem with his printer. The paper keeps getting jammed. He wants to work out the thickness of one sheet of paper in the pile of 500 sheets.
4 marksWhilst waiting for his printer to work the student watches an ornamental pendulum oscillate. He wants to know how long it takes for one oscillation of the pendulum.
Explain the method he should use to determine the time for one oscillation.
1 markThe student is getting bored waiting for the printer. He starts throwing a ball of scrunched-up paper across the room using an underarm throwing technique.
Estimate the distance the paper ball is thrown.
2 marksThe student then finds a tennis ball and uses the same underarm throwing technique to throw the ball across the room.
State whether the tennis ball will travel further than the scrunched-up paper ball. Explain your answer.
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2 marksEstimate the speed of an apple as it hits the ground after falling from a tree.
2 marksEstimate the number of kilowatt-hours used by a lightbulb if switched on for a whole day.
4 marksEstimate the density, in g cm−3, of the head of an adult person.
4 marksThe radius of the Earth is approximately 6.4 × 106 m.
Estimate the number of people it would take to circle the Earth holding hands.
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3 marksX–ray pulsars are detected by X–ray telescopes on a satellite in low Earth orbit 2000 km above the surface of the Earth.
Calculate the number of cubic millimetres (mm3) in a volume of 2000 km3.
3 marksX–rays from a pulsar travel at the speed of light and are detected on Earth with a wavelength of 8.0 nm.
Calculate the frequency of the X–rays. Give your answer to an appropriate number of significant figures.
3 marksX–rays from the nearest pulsar PSR J0109–1431 take 8.82 Gs to travel to Earth.
Calculate the number of oscillations of the X–rays from the pulsar to the surface of the Earth. Give your answer to an appropriate number of significant figures.
4 marksShow the distance from Earth to PSR J0109–1431 is around 280 light years.
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1 markDefine the term physical quantity.
1 markState one example of a quantity which is not a physical quantity.
3 marksPhysical quantities have symbols and units. Write a tick (✓) in all the boxes which are not valid physical quantities.
| E measured in J | format('truetype')%3Bfont-weight%3Anormal%3Bfont-style%3Anormal%3B%7D%3C%2Fstyle%3E%3C%2Fdefs%3E%3Ctext%20font-family%3D%22stix8ea284a28ff5a7e227709c23200%22%20font-size%3D%2236%22%20text-anchor%3D%22middle%22%20x%3D%2218.5%22%20y%3D%2237%22%3E%26%23x25A1%3B%3C%2Ftext%3E%3C%2Fsvg%3E) |
| φ measured in J kg−1 | format('truetype')%3Bfont-weight%3Anormal%3Bfont-style%3Anormal%3B%7D%3C%2Fstyle%3E%3C%2Fdefs%3E%3Ctext%20font-family%3D%22stix8ea284a28ff5a7e227709c23200%22%20font-size%3D%2236%22%20text-anchor%3D%22middle%22%20x%3D%2218.5%22%20y%3D%2237%22%3E%26%23x25A1%3B%3C%2Ftext%3E%3C%2Fsvg%3E) |
| Φ measured in Pa | |
| τ measured in s | |
| c measured in J kg−1 | |
| W measured in J N−1 | |
4 marksComplete the table providing reasonable estimates for some physical quantities.
|
quantity |
estimated magnitude |
|
Weight of an adult human |
|
|
3600 s |
|
|
Wavelength of green light |
|
|
20 °C |
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4 marks|
Physical Quantity |
SI Base Unit |
Order of Magnitude |
|
Acceleration of freefall Earth (g) |
m s−2 |
|
|
Stephan-Boltzmann constant (σ) |
|
10−7 |
|
Speed of a β particle |
|
|
|
Specific heat capacity of water (c) |
|
|
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