Solve the problem.
-A rock falls from a tower that is 176 feet high. As it is falling, its height is given by the formula $h = 176 - 16 t ^ { 2 }$. How many seconds (in tenths) will it take for the rock to hit the ground $( h = 0 )$ ?
A) $12.6 \mathrm { sec }$
B) $13.3 \mathrm { sec }$
C) $3.3 \mathrm { sec }$
D) $1936 \mathrm { sec }$

Question

Quizplus · Accepted Answer

To find the time it takes for the rock to hit the ground, set $h = 0$ and solve for $t$: $0 = 176 - 16t^2$. Rearranging gives $16t^2 = 176$, and dividing both sides by 16 gives $t^2 = 11$. Taking the square root of both sides gives $t = \sqrt{11}$, which is approximately $3.3$ seconds.

Solve the Problem h=176−16t2h = 176 - 16 t ^ { 2 }h=176−16t2

Solve the Problem $h = 176 - 16 t ^ { 2 }$