Solve the Problem $$H ( x ) = 40 - 4.9 x ^ { 2 }$$

question 16

Multiple Choice

Solve the problem.
-If a rock falls from a height of 40 meters on Earth, the height H (in meters) after x seconds is approximately $$H ( x ) = 40 - 4.9 x ^ { 2 }$$ When does the rock strike the ground? Round to the nearest hundredth, if necessary.

• A) 1.67 sec
• B) 8.16 sec
• C) 2.86 sec
• D) 1.29 sec