Measurements, uncertainties and SI units

How do you find Absolute uncertainty?

Range/2

How to fin the percentage uncertainty?

Range/2 x mean value

What is the total percentage uncertainty of the value of velocity when distance has 5% and time has 0.43% percentage uncertainties? And what is the absolute uncertainty of v if v= 8.7 ms

v=dxt

Has both so add them together

5.43% percentage uncertainty

Absolute uncertainty= 8,7×0.0543= +-0.5 ms

Why are log graphs better than regular graphs?

Log graphs are better because they are better at displaying data that is spread over multiple orders of magnitude.

Which part of y=mx+c is the gradient

M

If f²=T/4L²u what is the gradient?

m= 1/4L²u

Accuracy

How close a measurement is to its true value, influenced by the systematic and random errors of that measurement.

Precision

How close a set of repeated measurements are to one another but not the true value, influenced by the measurement’s random errors.

Random Error

The unpredictable variation in a measurement. These can be reduced by taking many repeated measurements and calculating their mean.

Zero error

when a measuring instrument shows a non-zero reading when the actual quantity being measured is zero, leading a systemic error in all readings.

Systematic Error

A constant shift in readings causing a deviation from the true value, due to the equipment or method being used and cannot be reduced by repeated measurements.

Repeatable

When the same person with the same equipment obtains the same result when doing the same experiment.

Reproducible

When different people with different equipment, measuring the same quantity, get a similar result.

Resolution

The smallest interval that a measuring device can measure.

What are the six SI units?

Kilogram

Kelvin

Candela

Metres

Moles

Seconds

Amps

When you calculate and uncertainty. When do you combine uncertainties?

ADDING and SUBTRACTING

A thermometer with an uncertainty of ±0.5 K shows the temperature of water falling from 298 ±0.5 K to 273 ±0.5K, what is the difference in temperature?

0.5 + 0.5 = 1K

= 25 +-1 K

a force of 91 ±3 N is applied to a mass of 7 ±0.2 kg, what is the acceleration of the mass? and it’s percentage uncertainty?

= 3.3% + 2.9%

= 6.2%

6.2% of 13 is 0.8

=13 ±0.8 m s^-2

What is the forumal for percentage uncertainty?

The radius of a circle is 5 ±0.3 cm, what is the percentage uncertainty in the area of the circle?

0.3/5 × 100= 6

6 × 2= 12cm³

When mutiplying or dividing uncertainties

add the percentage uncertainties

then work out the absolute uncertainty

suggest one way for experimental evidence to become valid

through peer reviewing

suggest 2 ways the application of science can be beneficial

developing medical treatments

carrying out research on prior knowledge

what does an application of science mean?

a use of scientific knowledge to carry out a specific action