Chapter 1 - Measurements and Units

Question 1

What are the seven fundamental units?

Answer 1

1) Meter(m)
2) Kilogram
3) Seconds(s)
4) Ampere(A)
5) Kelvin(K)
6) Mole(Mol)
7) Candela(cd)

Question 2

What can be said about the other units such as m/s^2?

Answer 2

They are derived from the fundamental units

Question 3

What is the definition of the order of magnitude?

Answer 3

Expressing a quantity in a plain power of 10

Question 4

What are the two types of errors?

Answer 4

Systematic, Random.

Question 5

Who is responsible for systematic errors

Answer 5

the observer and instrument.

Question 6

Who is responsible for random errors?

Answer 6

observers.

Question 7

How are the biases in measurement of systematic errors?

Answer 7

they are always too large or too small.

Question 8

Give an example of a systematic error-

Answer 8

when you are measuring water from a graduated cylinder, you may read the volume wrong if the cylinder is tilted.

Question 9

How are random errors revealed?

Answer 9

They are revealed when repeated measurements of the same quantity show a spread of values, some being too large or some being too small.

Question 10

How are the biases in random errors?

Answer 10

The results are unbiased and unpredictable.

Question 11

Give an example of a random error.

Answer 11

f a person is running a 100m race and a group of people time it using a stopwatch, some readings will be inaccurate because the individuals started it too early. Other readings may be inaccurate because they started the stopwatch too late.

Question 12

When is a reading accurate?

Answer 12

When the systematic error is minimal and the reading is close to its true value.

Question 13

When is a reading precise?

Answer 13

When the random error is small. If an experiment was repeated multiple times, the values will be close together.

Question 14

Why do we calculate averages?

Answer 14

Averages are the best estimate for the quantity?

Question 15

What is a rule for averages and uncertainties?

Answer 15

The value of the average period must be expressed as the same precision as the uncertainty.

Question 16

if we have a value 28± 0.4 cm for the length of a book, what is the name given to 28 ?

Answer 16

the mean or best estimate.

Question 17

if we have a value 28± 0.4 cm for the length of a book, what is the name given to 0.4?

Answer 17

The absolute uncertainty.

Question 18

What is the fractional uncertainty?

Answer 18

The ratio of the absolute uncertainty to the mean value.

Question 19

What is the percentage uncertainty?

Answer 19

The fractional uncertainty multiplied by 100.

Question 20

What is a rule for adding or subtracting values with uncertainties?

Answer 20

If we need to add or subtract values, we always add uncertainties.

Question 21

What is a rule for multiplying or dividing values with uncertainties?

Answer 21

If we need to multiply or divide values, the fractional uncertainty of the result is the sum of the fractional uncertainties of the quantities

Question 22

What is a rule for raising a value to the power n and the value has an uncertainty?

Answer 22

If we need to raise a value to the power n, the fractional uncertainty of the result is the fractional uncertainty of the value multiplied by the absolute value of n

Question 23

What is a rule for rooting a value to n?

Answer 23

If we need to root a value to n, the fractional uncertainty of the result is the reciprocal of n multiplied by the fractional uncertainty of the value.