# Aviation A helicopter hove 40 ft above the ground. Then the helicopter climbs at a rate of 21 ft/s. Write a rule that represents the helicopter's height h above the ground as a function of time t. What is the helicopter's height after 45 s?

##### 1 Answer

#### Explanation:

Let height increase be positive value

Let height decrease be negative value

Let time in seconds be ..............................

Let height in feet at any time

Given: height increase rate is 21 feet per second

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

After 1 second the height increases by 21 feet

After 2 seconds the height has increased by

After 3 seconds the height has increased by

So after

So we have:

height at t seconds = initial height + change in height upwards

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

So for 45 seconds we have:

Note that height at 45 seconds is written as