10 minutes maximum! Can you do it in 5?

1. The thickness of a piece of cardboard is measured as 5 ± 1mm . Which of these gives the correct error as a fraction, a percentage and an absolute error?

Percentage error 
Fractional error 
Absolute error (mm) 
A 
20 
2 
1 
B 
20 
0.2 
1 
C 
25 
5 
0.2 
D 
20 
0.2 
5 


2 4. A student measures the acceleration of gravity by dropping a lead sphere. The experiments lead to 4 results:
g = 11.4, 11.5, 11.5, 11.6 m s^{2}
Average = 11.5 m s^{2}
(The accepted answer is 9.8m s^{2} to 2 sig figs). 

2. The results above can best be described as
 A. precise and accurate
 B. neither precise nor accurate
 C. accurate but not precise
 D. precise but not accurate


3. The student is asked to write a concise conclusion. Which numerical answer best completes this sentence?
The experiment leads to a final result for the acceleration of gravity as...
 A. 11.5 ± 1.7 m s^{2}
 B. 9.8 ± 1.7 m s^{2}
 C. 9.8 ± 0.2 m s^{2}
 D. 11.5 ± 0.1 m s^{2}


4. The likely cause for the results above is identified as the stop watch being stopped too quickly, making all the time readings out by a similar margin. This kind of error is called
 A. a random error
 B. a ^{}calculation error
 C. a description error^{}
 D. a systematic error^{}
 
5 A ruler is used to measure the depth of a liquid as shown in the diagram. Unfortunately the student has missed the fact that the ruler has a short piece of plastic before the zero mark. 


Which of these best describes this error and the consequent effect on the depth reading?

Type of error 
Effect on recorded reading 
A 
random 
reading is too low 
B 
systematic 
reading is too low 
C 
random 
reading is too high 
D 
systematic 
reading is too high 
 
6. A digital balance gives a mass reading as shown in the diagram. The mass of the block shown should be recorded as
 A. 72.0 ± 0.05 g
 B. 72.0 ± 0.1 g
 C. 72.0 ± 0.5 g
 D. 72 ± 1 g



7. A cube has a side length of 10 cm ± 1 cm. The volume of the cube is
 A. 1000 ^{}± 3 cm^{3}
 B. 1000 ^{}± 1 cm^{3}
 C. 1000 ^{}± 300 cm^{3}
 D. 1000 ^{}± 100 cm^{3}
 
8. Box A has a mass of 14 ± 2 kg. Box B has a mass of 24 ± 3 kg.
The total mass of both boxes is
 A. 38 ± 2 kg
 B. 38 ± 2.5 kg
 C. 38 ± 3 kg
 D. 38 ± 5 kg
 
9&10. A ball rolls down a slope of length 20 ± 2cm in a time of 5 ± 1 s.


9. Which of these correctly states the percentage errors in the length and time readings?

Length error (%) 
Time error (%) 
A 
2 
1 
B 
10 
20 
C 
0.1 
20 
D 
10 
1 
 
10. The average velocity of the ball is 4cm s^{}^{1}. The total percentage error in the velocity is
 A. 10%
 B. 20%^{}
 C. 30%^{}
 D. 40%
 
