While hiking, Marek throws a rock off a cliff that is roughly 10 meters above a lake. This situation is modeled by the equation h=−4.9t2+10 , with h representing the height in meters and t the time in seconds. If you were to set up a table to determine when the rock hits the water, what would be a reasonable scale for the range?(1 point) Responses

1 answer

To determine when the rock hits the water using the given equation \( h = -4.9t^2 + 10 \), we need to find when the height \( h \) is equal to 0 (the height of the water).

Setting the equation to 0 gives:

\[ 0 = -4.9t^2 + 10 \]

Solving for \( t \):

  1. Rearranging the equation: \[ 4.9t^2 = 10 \]

  2. Divide both sides by 4.9: \[ t^2 = \frac{10}{4.9} \approx 2.04 \]

  3. Now take the square root of both sides: \[ t \approx \sqrt{2.04} \approx 1.43 \text{ seconds} \]

To create a table, you want a reasonable scale for the range of time \( t \), which will help you see the rock's height at various times.

Since the rock hits the water at about \( t = 1.43 \) seconds, a reasonable scale for the time (t) might range from 0 to about 2 seconds, collecting values that might include increments of 0.1 seconds. This would look like:

| Time (t) | Height (h) | |----------|------------| | 0.0 | 10 | | 0.1 | 9.95 | | 0.2 | 9.80 | | 0.3 | 9.19 | | 0.4 | 8.16 | | 0.5 | 6.75 | | 0.6 | 4.96 | | 0.7 | 2.79 | | 0.8 | 0.24 | | 0.9 | -2.79 | | 1.0 | -5.76 | | 1.5 | -14.63 |

In conclusion, a reasonable scale for the range of time for the table would be 0 to 2 seconds with increments of 0.1 seconds.