A micrometeor has a mass of 0.005 grams. When it enters Earth’s atmosphere, it travels at 21,000 meters per second. What is its kinetic energy when it enters Earth’s atmosphere?

KE=1/2mv/2

Responses

1,102,500 J

0.0525 J

1,102.5 J

2,205 J

1 answer

To calculate the kinetic energy (KE) of the micrometeor when it enters Earth's atmosphere, we can use the kinetic energy formula:

\[ KE = \frac{1}{2} mv^2 \]

where:

  • \( m \) is the mass (in kilograms),
  • \( v \) is the velocity (in meters per second).

First, we need to convert the mass from grams to kilograms:

\[ m = 0.005 \text{ grams} = 0.005 \times 10^{-3} \text{ kg} = 0.000005 \text{ kg} \]

Now, we can substitute the values into the kinetic energy formula:

\[ v = 21,000 \text{ m/s} \]

Now we calculate \( KE \):

\[ KE = \frac{1}{2} \times 0.000005 \text{ kg} \times (21,000 \text{ m/s})^2 \]

Calculating \( v^2 \):

\[ (21,000)^2 = 441,000,000 \text{ m}^2/\text{s}^2 \]

Now substitute it back into the kinetic energy equation:

\[ KE = \frac{1}{2} \times 0.000005 \times 441,000,000 \] \[ KE = 0.0000025 \times 441,000,000 \] \[ KE = 1,102.5 \text{ J} \]

Thus, the kinetic energy of the micrometeor when it enters Earth's atmosphere is:

1,102.5 J

The correct response is: 1,102.5 J