Question

A shooting star is a meteoroid that burns up when it reaches Earth’s atmosphere. Many of these meteoroids are quite small. Compare the kinetic energy of a shooting star to that of a moving car.What is the kinetic energy of a meteoroid of mass 4.96 g moving at a speed of 49.1 km/s?

Answer 1

we are asked to determine the kinetic energy of an object that has a mass of 4.96g. To do that we will use the following formula:

$K=\frac{1}{2}mv^2$

Where:

$\begin{gathered} K=\text{ kinetic energy }\lbrack J\rbrack \\ m=\text{ mass }\lbrack kg\rbrack \\ v=\text{ velocity }\lbrack\frac{m}{s}\rbrack \end{gathered}$

First, we will convert the mass into kilograms using the following conversion factor:

$1\operatorname{kg}=1000g$

Now we multiply the mass by the conversion factor in decimal form:

$4.96g\times\frac{1\operatorname{kg}}{1000g}=0.00496\operatorname{kg}$

Now, we convert the velocity into meters per second by converting kilometers into meters. To do that we will use the following conversion factor:

$1\operatorname{km}=1000m$

Now, we multiply the velocity by the conversion factor:

$49.1\frac{\operatorname{km}}{s}\times\frac{1000m}{1\operatorname{km}}=49100\frac{m}{s}$

Now, we substitute the values in the formula for the kinetic energy:

$K=\frac{1}{2}(0.00496)(49100\frac{m}{s})^2$

Solving the operations:

$K=5.99\times10^6J$

And thus we have determined the kinetic energy of the meteorite.