Physics quiz 1.2

1 kg =

2.2 lbs

What is the difference between accuracy and precision?

Accuracy is the indication of how close a series of measurements are to an accepted value, while precision is an indication of the frequency with which a measurement produces the same results.

8. You are driving on a highway that posts a 65 mi/h speed limit. The speedometer is accurate within 5mi/h. a. What speed should you drive as shown on the speedometer to guarantee that you will not exceed the speed limit?

60 mi/h

What is the difference between a random error and a systematic error?

A systematic error can be corrected by a calculator while a random error cannot be corrected by calculation.A systematic error can be corrected by calculation while a random error cannot be corrected by calculation. If a group of people weighed an object and the readings were very close to each other, then the uncertainty in measurement is said to contain a random error. Any measurement has limited accuracy, and users are unable to read an instrument beyond some fraction of the smallest unit shown. The uncertainty of a measurement is the range within which the actual value is likely to fall, compared to the measured value.

For the first part of our investigation, we found the distance of the hallway by measuring the stride length of one person and counting how many strides it took them to walk the given distance. When we did this, we came up with distances that were quite different from each other. What would be the best way to achieve the most accurate value for the length of the hallway?

Take the average of the values of each group

b. A mid-sized automobile with a full tank of gas can travel from Boston to New York City without having to refuel.

The distance from New York City to Boston is about 300 miles. A mid-sized vehicle might get 25 miles to the gallon, making its gasoline usage around 12 gallons. Most mid-sized vehicles would have a 16-gal tank.

b. What could a passenger in the vehicle do while you are driving to estimate how accurate the speedometer is? (Hint: the road has mile markers, and the passenger has a wristwatch that shows seconds).

The passenger may watch the mile markers and mark the time when they are passed. A driver traveling at 60 mi/h would travel 1 mile in 60 seconds (60mi/h is 60 miles in 60 min), so if the vehicle is traveling 60mi/h, the next mile marker should be passed in exactly 60 s.

A 2-L bottle of soft drink is enough to serve 12 people at a meeting

There are about 4 cups in 1 liter There are about 33 oz in 1 liter. A standard water bottle is about 20 oz.

_________ can never be completely eliminated.

Uncertaincy

Are uncertainties in measurements always present?

Yes. There is no exact measurement. There will always be uncertainty surrounding a given value. Uncertainty in measurement can never be eliminated because all measurements are made around a certain value thought to be true. The difference between the true value and the actual value produces an uncertainty in the measurement.

measurements can vary with ________ or _________.

accuracy, precision

what is a unit used to measure a current?

ampere (1A= 1c/s)

systematic error

an error produced by using the wrong tool or using the tool incorrectly for measurement and can be corrected by calculation

accuracy

an indication of how close a series of measurements are to an accepted value

precision

an indication of the frequency with which a measurement produces the same results

random errors

errors that cannot be corrected by calculating

a meter stick with only centimeters would have a _________ uncertainty than a meter stick

greater

what is a unit used to measure temperature?

kelvin (k)

the _________ ____ and the __________ _____ ___ _________ are responsible for the uncertainty.

measuring tool, person doing the measuring

a large uncertainty can occur if a __________ measuring is not ________ with _________ the stick with the length is being measured

person, aligning