An asteriod is heading toward Mars at the rate of 7.7 x 10^4 mi./hr. If the asteroid is 3.311 x 10^8 miles away from Mars, how many hours will it be before it hits mars? write the answer in scientific notation, expressed to the exact decimal place.

5 answers

To find the time it takes for the asteroid to hit Mars, we can use the formula:

\[ \text{Time} = \frac{\text{Distance}}{\text{Speed}} \]

Given:

  • Distance = \(3.311 \times 10^8\) miles
  • Speed = \(7.7 \times 10^4\) miles/hour

Now, we substitute the values into the formula:

\[ \text{Time} = \frac{3.311 \times 10^8 \text{ miles}}{7.7 \times 10^4 \text{ miles/hour}} \]

To perform the division in scientific notation, we divide the coefficients and subtract the exponents:

  1. Divide the coefficients:

\[ \frac{3.311}{7.7} \approx 0.430 \]

  1. Calculate the exponents:

\[ 10^8 \div 10^4 = 10^{8-4} = 10^4 \]

Putting it all together, we have:

\[ \text{Time} \approx 0.430 \times 10^4 \]

To express this in proper scientific notation, we adjust \(0.430\) to \(4.30\) and decrease the exponent by 1:

\[ 4.30 \times 10^3 \text{ hours} \]

Therefore, the asteroid will hit Mars in approximately:

\[ \boxed{4.30 \times 10^3} \text{ hours} \]

A field of 3.9 mi^2 is being subdivided into 1.3 x 10^3 family gardens. How many square miles will there be in each garden? Write the answer in scientific notation.

To find the area of each family garden, we can use the formula:

\[ \text{Area per garden} = \frac{\text{Total area}}{\text{Number of gardens}} \]

Given:

  • Total area = \(3.9 , \text{mi}^2\)
  • Number of gardens = \(1.3 \times 10^3\)

Substituting the values into the formula:

\[ \text{Area per garden} = \frac{3.9 , \text{mi}^2}{1.3 \times 10^3} \]

Now, let's perform the division:

  1. Divide the coefficients:

\[ \frac{3.9}{1.3} \approx 3.0 \]

  1. For the exponents, we can express \(3.9\) in scientific notation as \(3.9 \times 10^0\):

\[ \text{Area per garden} = \frac{3.9 \times 10^0}{1.3 \times 10^3} = \frac{3.9}{1.3} \times 10^{0-3} = 3.0 \times 10^{-3} \]

Thus, the area per garden is:

\[ \text{Area per garden} = 3.0 \times 10^{-3} , \text{mi}^2 \]

Therefore, the area of each family garden in scientific notation is:

\[ \boxed{3.0 \times 10^{-3}} , \text{mi}^2 \]

Charlee is using her calculator to find the product of two large numbers. Her calculator shows 1.78E12 on the display. Interpret what this means.

The notation \(1.78E12\) is a way of representing numbers in scientific notation, which is often used for very large or very small numbers. In this format:

  • \(E\) can be thought of as "times ten raised to the power of".
  • The number before the \(E\) is the coefficient.
  • The number after the \(E\) is the exponent of 10.

So, \(1.78E12\) means:

\[ 1.78 \times 10^{12} \]

To interpret what this means in a more standard format, you can multiply \(1.78\) by \(10^{12}\):

\[ 1.78 \times 10^{12} = 1,780,000,000,000 \]

This is a 1 followed by 12 zeros.

Therefore, \(1.78E12\) represents the value 1 trillion, 780 billion.

In summary, \(1.78E12\) indicates that the product of the two large numbers Charlee is calculating is \(1.78 \times 10^{12}\), or 1,780,000,000,000 in standard decimal notation.