P11 Kinetmatics (1) - Quantities and units

How was the meter originally defined?

• Half a person's height

• 1/10,000,000 the distance from the equator to the North pole

• The distance between two engraved lines on a platinum-iridium bar

• The distance that light travels through a vacuum in 1/299,792,458 of a second

What is the modern definition of the kilogram?

• 1000 grams

• An equation in terms of the second, meter, and Planck’s constant

• The mass of a platinum-iridium cylinder kept near Paris

• The mass of 1 L of water

Why did the second have to be redefined?

• Cesium atoms have changed

• Earth's rotation is changing

• The seasons change through the year

• Because it was an arbitrary unit

Electrical current is measured in

• Amperes

• Volts

• Kelvins

• Prefixes

What is the freezing point of water in kelvin?

• 0

• 273

• 32

• 212

What occurs at 0 K?

• There is no kinetic energy of atoms

• Water freezes

• It is as cold as the coldest temperature on earth

• Liquid nitrogen freezes

The metric prefix for 1000 of something is

• micro

• mega

• deci

• kilo

What is 0.00037 in scientific notation?

• 37 x10^-5

• 3.7 x10^-4

• 3.7 x10⁴

• 3.7

Convert 26.6 kg to grams

• 26600

• 0.000266

• 26.6

• 266

How close the measurements are to the correct value is the

• Accuracy

• Precision

• Correctness

• Uncertainty