wri and solve an equation to find the elapsed time until the performer plants in the net

Question

wri and solve an equation to find the elapsed time until the performer plants in the net

While participating a tightrope walk at s height of 20 feet , a circus performer slips and falls into a safety net 15 feet below . The function h(t) = -16t²+ 20 , where t represents time measured in seconds, gives the performer height above the ground (in feet) as he falls

Answer 1

To find out how

-16t² represents gravity

h(t) represents height above ground.

We are looking for time to fall into the safety net.

Note: the tightrope is 20 feet above ground, the net is 15 feet below the tightrope.

20 -15 = 5

So the net is 5 feet above ground.

So the goal then becomes find t out of

5 = -16t² +20

Subtract 20 from both sides.

-15 = -16 t ²

Some students are tempted to add 16 to both sides. However, we need to separate the -16 from t². The -16 and t² are attached to each other by multiplication. The opposite of multiplication is division, divide by -16 on both sides. Thankfully, our negatives cancelled.

15 = t²

16

Square root both sides,

square root (15/16) = t

Powers of fractions often simplify by applying to the numerator and the denominator.

square root (15) = t

4

or t = 0.968 seconds.