A gust of wind forces a rock to fall off a cliff that's 20 feet high. This is represented by the function h(t) = –16t2 + 20, where t represents the time measured in seconds, and h represents height above the ground. Approximate how many seconds it takes for the rock to hit the ground. Answer Options:

A.) 1.25 seconds

B.) 1.5 seconds

C.) 1.12 seconds

D.) 1 second

C.) 1.12 seconds

Step-by-step explanation:

Hi, to answer this question we have to substitute h=0 (when the rock hits the ground the height above it is 0) in the equation given:

h (t) = –16t2 + 20

Solving for t (time)

0= –16t2 + 20

16t2=20

t2=20/16

t=√1.25 =1.12 seconds (option C)

Feel free to ask for more if needed or if you did not understand something.

introduction, methodology, results, discussion

step-by-step explanation:

an observational study is one which consists of actual observation to record data and then analyse the data.

there are a number of factors that should be analyzed before starting an observational study.

the main four factors are:

i) introduction:   this should be analysed to check whether the purpose of the study is correctly established and the data recorded are appropriate for the study

methodology:   the method of collecting the data, such as whether randomly selected, and whether sample size matches with the population to be studied, whether questions asked are easy to answer by common men, etc.

results: then results such as summary of data with comments should be studied thoroughly

discussion:   the last is the discussion, this can be either by management people or persons who are all interested , etc.

its kind of blurry. can you put a clearer pic?

step-by-step explanation: