Acliff diver dives from 17m above the water. the diver’s height above the water, h(t) in metres after t seconds is modelled by h(t) = -4.9t2 + 1.5t + 17. determine when the diver was 5 m above the water.
: (

If you want to round to the nearest hundredths, the answer is 1.73 seconds.

Step-by-step explanation:

So we want to solve h(t)=5 for t because this will give us the time,t, that the diver was 5 m above the water.

My goal here in solving this equation is to get it into so I can use the quadratic formula to solve it.

The quadratic formula is .

So let's begin that process here:

Subtract 5 on both sides:

So let's compare the following equations:

.

Now we are ready to insert in the quadratic formula:

I know this can look daunting when putting into a calculator.

But this is the process I used on those little calculators back in the day:

Put the thing inside the square root into your calculator first.  I'm talking about the .

This gives you:  237.45

Let's show what we have so far now:

I'm going to put the denominator, 2(-4.9), into my calculator now.

So this gives us two numbers to compute:

I'm actually going to type in -1.5-sqrt(237.45) into my calculator, as well as, -1.5+sqrt(237.45).

We are going to use the positive number only for our solution.

So we have the answer is whatever that first fraction is approximately:

.

The answer is approximately 1.73 seconds.

addition

step-by-step explanation: