CH 1-3 REVIEW

a meter is defined as

the distance that light travels in a vacuum in a time of 1/299792458s

A kilogram was defined to be…

the mass of a platinum-iridium cylinder kept at the international Bureau of Weights and measures

the standard unit of time (seconds) are defined to be

the electromagnetic waves emitted by cesium-133 in an atomic clock

accuracy

how close a measurement is to the correct value for that measurement

Precision

refers to how close the agreement is btwn repeated measurements (which are repeated in the same conditions)

Which statement is true about a measurement that is precise but not accurate?

They measurements are consistent but far from the true value

What does accuracy in measurement refer to?

How close a measurement is to the true value.

In what situation does the car have a westward acceleration?

The car travels westward and speeds up

A train has a constant velocity of 77.3 m/s due north. While the train is still moving due north, the operator applies the brake, and the magnitude of train's velocity reduces to 59.4 m/s. What is the direction of train’s average acceleration?

south

In which one of the following situations does the car have a southward acceleration?

The car travels northward and slows down