High School Physics : Introductory Principles

Study concepts, example questions & explanations for High School Physics

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Example Questions

Example Question #1 : Understanding Accuracy And Precision

An brand of fruit snacks claims that each bag of fruit snacks has a mass of . After weighing three bags, Wally observes the masses to be , , and  .

How can Wally describe the accuracy and precision of the first bag he measured?

Possible Answers:

Neither accurate nor precise

There are insufficient data points to draw a conclusion

Precise, but not accurate

Accurate and precise

Accurate, but not precise

Correct answer:

Accurate, but not precise

Explanation:

The claim for the mass of the first bag is accurate; the brand says there should be in each bag and there was in the first bag.

The claim on the first bag is not precise, as the results are not replicated universally throughout the experiment. The masses of the bags fluctuate, with the average of all three bags equal to .

Example Question #1 : Understanding Accuracy And Precision

A bowman is shooting arrows at a target. Which of the following demonstrates high accuracy but low precision?

Possible Answers:

The bowman consistently hits the bullseye

The bowman consistently hits around the target but never hits the bullseye

The bowman consistently hits to the left of the target

The bowman consistently misses the target and hits a tree in the same spot

The bowman consistently hits to the right of the bullseye

Correct answer:

The bowman consistently hits around the target but never hits the bullseye

Explanation:

Accuracy is measured as the degree of closeness to the actual measurement. In our case, accurate shots will hit the bullseye. Precision is measured as the degree of closeness of one measurement to the next. In our case, precise shots will be clustered together.

To get high accuracy but low precision, measurements must center around the target value but be variable. The bowman's arrows will not be clustered (low precision), but will be accurately distributed around the bullseye. If all the shots were averaged, the bullseye would be at the center.

Example Question #5 : Understanding Accuracy And Precision

Which of these is an example of high precision?

Possible Answers:

A student correctly calculates the mass of an object to be 54kg

A student tries to throw a pencil into the garbage can and makes it in

A student correctly calculates the acceleration due to gravity to be 

An archer hits the bulls-eye

An archer hits the same spot on the target three times in a row

Correct answer:

An archer hits the same spot on the target three times in a row

Explanation:

Precision is a measure of reproducibility. If multiple trials produce the same result each time with minimal deviation, then the experiment has high precision. This is true even if the results are not true to the theoretical predictions; an experiment can have high precision with low accuracy.

In contrast, accuracy is the measure of difference between a calculated value and the true value of a measurement. High accuracy demands that the experimental result be equal to the theoretical result.

An archer hitting a bulls-eye is an example of high accuracy, while an archer hitting the same spot on the bulls-eye three times would be an example of high precision.

Example Question #6 : Understanding Accuracy And Precision

Which of these is an example of high accuracy?

Possible Answers:

A student throws three pencils into the trash can, but misses and hits the window each time

A student calculates the acceleration due to gravity to be  using three different methods

A student repeatedly calculates the mass of an object to be 49 grams, when the true mass is 52 grams

An archer hits the same spot on the target three times in a row

An archer hits the bulls-eye

Correct answer:

An archer hits the bulls-eye

Explanation:

Accuracy is the measure of difference between a calculated value and the true value of a measurement. High accuracy demands that the experimental result be equal to the theoretical result.

In contrast, precision is a measure of reproducibility. If multiple trials produce the same result each time with minimal deviation, then the experiment has high precision. This is true even if the results are not true to the theoretical predictions; an experiment can have high precision with low accuracy.

An archer hitting a bulls-eye is an example of high accuracy, while an archer hitting the same spot on the bulls-eye three times would be an example of high precision.

Example Question #1 : Understanding Significant Figures

How many significant figures should be kept when multiplying ?

Possible Answers:

1

2

5

0

3

Correct answer:

3

Explanation:

Always keep the least number of significant figures. Two types of figures can be significant: non-zero numbers and zeroes that come after the demical place. 

 has 3 significant figures while  also has 3.

Therefore, your answer should also have 3 significant figures.

Example Question #2 : Understanding Significant Figures

How many significant figures are in ?

Possible Answers:

Zero

Five

One

Four

Seven

Correct answer:

One

Explanation:

There are two categories that count as significant figures: non-zero numbers before the decimal point and everything after the decimal point. Since the number given is , there is only one non-zero number before the decimal point.

This number could have been rounded from any variation past the first digit, and we cannot assume that it is exact. To write this number in exact terms, we must use scientific notation or a decimal.

Example Question #3 : Understanding Significant Figures

How many significant figures should be in in the answer to the calculation?

Possible Answers:

One

Four

Three

Five

Two

Correct answer:

One

Explanation:

There are two categories that count as significant figures: non-zero numbers before the decimal point and everything after the decimal point.

When performing any operation between two numbers with different significant figures, always base it off the smallest number of significant figures. In this case,  has only one significant figure; therefore our answer should also have only one significant figure.

Example Question #4 : Understanding Significant Figures

How many significant figures should be in the answer to the calculation?

Possible Answers:

Two

Zero

One

Three

Six

Correct answer:

One

Explanation:

Your answer should have the same number of significant figures as the term with the fewest significant figures. There are only two categories that qualify as significant figures: any terms after the decimal point and non-zero digits before the decimal.

In this problem,  has the fewest number of significant figures: only one. has three significant figures, but its precision is diminished by multiplying by a less precise term.

Example Question #1 : Understanding Significant Figures

Solve the expression with the proper number of significant figures.

Possible Answers:

Correct answer:

Explanation:

When multiplying or dividing, the answer must have the same number of significant figures as the term with the fewest significant figures in the problem. In this question, the one term () has only significant figure, and the other term () has four. Our final answer must match the term with the fewest significant figures: one. It is important to remember that zeroes after a decimal are significant figures, and determine the precision of a value. Zeroes before a decimal, such as in , simply serve as place holders, and are no considered significant unless there is a decimal or scientific notation to clarify the term.

Round to the ones place to get an answer with only one significant figure.

Example Question #72 : Introductory Principles

Solve the expression with the proper number of significant figures.

Possible Answers:

Correct answer:

Explanation:

When multiplying or dividing, the answer must have the same number of significant figures as the term with the fewest significant figures in the problem. In this question, the one term () has two significant figures, and the other term () has three. Our final answer must match the term with the fewest significant figures: two.

Round to the tens place to get an answer with only two significant figures.

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