If you launch an object straight up from the surface of the Earth and want it to avoid being returned back to Earth by gravity, it must leave the surface of Earth at what’s called the escape velocity. 1
en.wikipedia.org/wiki/Escape_velocity
Escape velocity is also defined for other large objects such as planets, moons, and stars. The escape velocity from the surface of the Earth is about \(11,200\) meters per second. The escape velocity from the surface of the Moon is about \(21.25%\) of the escape velocity from the surface of the Earth. Calculate the escape velocity from the surface of the Moon in meters per second using the correct number of significant figures.
\(2.38 \times 10^{3}\) meters per second.
Correct!
\(2.380 \times 10^{3}\) meters per second.
Try again. \(11,200\) meters per second has three significant figures, and \(21.25%\) has four significant figures. Since we are multiplying, the answer should have three significant figures.
\(59.1\) meters per second.
Try again. Try multiplying \(11,200\) meters per second by \(0.2125\) (which is \(21.25%\) expressed as a decimal).
\(59.09\)
Try again. Try multiplying \(11,200\) meters per second by \(0.2125\) (which is \(21.25%\) expressed as a decimal). Also, double check your significant figures.
Checkpoint2.3.2.
The Moon’s surface can reach a maximum temperature of \(121\,^{\circ}\text{C}\) during the day and drop to \(-178.89\,^{\circ}\text{C}\) at night. What is the average surface temperature of the Moon over one full day-night cycle, rounded to the correct number of significant figures?
\(-29\,^{\circ}\text{C}\)
Correct!
\(-28.9\,^{\circ}\text{C}\)
Try again. Since one measurement, \(121\text{,}\) has zero decimal places, the result must be rounded to zero decimal places as well.
\(150\,^{\circ}\text{C}\)
Try again. The basic definition of an average is to add all the numbers together and then divide by the total number of values. For example, the average of \(1\text{,}\)\(4\text{,}\) and \(7\) is: \(\frac{1+4+7}{3} = 4\)
\(149.95\,^{\circ}\text{C}\)
Try again. Double check your significant figures. ALso, the basic definition of an average is to add all the numbers together and then divide by the total number of values. For example, the average of \(1\text{,}\)\(4\text{,}\) and \(7\) is: \(\frac{1+4+7}{3} = 4\)
