Physics Midterm Review

Which of the following is an area of physics that studies motion and its causes?

• a. thermodynamics

• b. mechanics

• c. quantum mechanics

• d. optics

Answer explanation

Mechanics is the branch of physics that deals with the study of motion and the forces that cause it. It encompasses concepts such as velocity, acceleration, and the laws of motion, making it the correct choice.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

NGSS.MS-PS2-4

What two dimensions, in addition to mass, are commonly used by physicists to derive additional measurements?

• a. length and width

• b. area and mass

• c. length and time

• d. velocity and time

Answer explanation

In physics, length and time are fundamental dimensions used to derive various measurements, such as speed and acceleration. Thus, the correct answer is c. length and time.

Tags

NGSS.HS-PS4-1

The symbol mm represents a

• a. micrometer

• b. millimeter

• c. megameter

• d. manometer

Answer explanation

The symbol 'mm' stands for millimeter, which is a unit of length equal to one thousandth of a meter. It is commonly used in various fields such as engineering and science.

The SI base unit used to measure mass is the

• a. meter

• b. second

• c. kilogram

• d. liter

Answer explanation

The SI base unit for mass is the kilogram, which is the standard unit used in scientific measurements. The other options (meter, second, liter) measure length, time, and volume, respectively.

The SI base unit for time is

• a. 1 day

• b. 1 hour

• c. 1 minute

• d. 1 second

Answer explanation

The SI base unit for time is the second, which is the standard measurement used in scientific contexts. Other options like day, hour, and minute are derived units and not the base unit.

The most appropriate SI unit for measuring the length of an automobile is the

• a. micron

• b. kilometer

• c. meter

• d. nanometer

Answer explanation

The length of an automobile is best measured in meters, as it is a practical unit for everyday objects. Microns and nanometers are too small, while kilometers are too large for this context.

The radius of Earth is 6 370 000 m. Express this measurement in km in scientific notation with the correct number of significant digits.

• a. 6.37 x 10^6 km

• b. 6.37 x 10^3 km

• c. 637 x 10^3 km

• d. 63.7 x 10^4 km

Answer explanation

To convert 6,370,000 m to km, divide by 1,000, resulting in 6,370 km. In scientific notation, this is 6.37 x 10^3 km, which has three significant digits, matching choice b.

A lack of precision in scientific measurements typically arises from

• a. limitations of the measuring instrument.

• b. human error.

• c. lack of calibration.

• d. too many significant figures.

How does a scientist reduce the frequency of human error and minimize a lack of accuracy?

• a. Take repeated measurements.

• b. Use the same method of measurement.

• c. Maintain instruments in good working order.

• d. all of the above

Answer explanation

A scientist can reduce human error and improve accuracy by taking repeated measurements, using consistent methods, and maintaining instruments. Therefore, the correct answer is d. all of the above.

Three values were obtained for the mass of a metal bar: 8.83 g; 8.84 g; 8.82 g. Based on these values, what is the most accurate mass? The known mass is 10.68 g. The values are

• accurate.

• precise.

• both accurate and precise.

• neither accurate nor precise.

Answer explanation

Accuracy refers to how close a measurement is to the true value, while precision indicates the consistency of repeated measurements. This value is precise but not accurate.