Teacher's notes and answers to questions in the book - Hodder Plus ...

WJEC GCSE Additional Science Teacher’s Notes
2. Is there a pattern in your results What is the average value of force/acceleration How does this
compare to the mass (in kg) of the glider plus slotted masses
F/a should be constant with a value (approximately) equal to the total accelerating mass
(glider + mass stack).
3. Plot a graph of resultant force (y-axis) against acceleration (x-axis). Confirm that it is a straight line
and draw a best-fit straight line through your results (starting at the origin).
Student graphs.
4. Measure and calculate the gradient (slope) of the graph.
5. Compare your gradient to the mass (in kg) of the glider plus the slotted masses.
Gradient should (approximately) equal total accelerating mass.
Questions
8. A fully laden Soyuz spacecraft (mass = 7150 kg) accelerates away from the ISS towards its re-entry
point with an acceleration of 2 m/s 2 relative to the ISS. Calculate the resultant force on the Soyuz
spacecraft.
F = ma = 7150 × 2 = 14 300 N
9. At lift-off, the combined thrust of the SRB and main Shuttle engines is 30 400 000 N. The total weight of
the Space Shuttle at lift-off is 20 407 000 N, as its mass is 2 040 700 kg.
a Calculate the resultant force on the Space Shuttle at take-off.
Resultant force = thrust – weight = 30 400 000 – 20 407 000 = 9 993 000 N
b Calculate the acceleration of the Space Shuttle at take-off.
F = ma
F
a m
9 993 000
2 040 700
4.9 m/s
2
10. An astronaut is using the manned manoeuvring unit (MMU) to examine solar panels on the ISS. The
MMU generates a small thrust force of 60 N, which accelerates the MMU and the astronaut at 0.25
m/s 2 . Calculate the mass of the MMU plus the astronaut. If the astronaut has a mass of 80 kg, what is
the mass of the MMU
F = ma
F
m a
60 240 kg mass of MMU = 240 – 80 = 160 kg
0.25
_ Newton’s second law and momentum_____________
(pages 184–87)
Questions
11. During T+200 s and T+300 s of a Space Shuttle launch (i.e. between 200 s and 300 s after launch), the
Shuttle (mass = 2 040 700 kg) accelerates from 2600 m/s to 4400 m/s.
a Calculate the momentum of the Shuttle at:
i T+200 s p = mv = 2 040 700 × 2 600 = 5 306 000 000 kg m/s
ii T+300 s p = mv = 2 040 700 × 4 400 = 8 979 000 000 kg m/s
b Calculate the change in momentum between these times.
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