1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Mumz [18]
3 years ago
13

In the air, it had an average speed of 16m/s . In the water, it had an average speed of 3 m/s before hitting the seabed. The tot

al distance from the top of the cliff to the seabed is 127 meters, and the stone's entire fall took 12 seconds.How long did the stone fall in air and how long did it fall in the water?
Mathematics
1 answer:
Step2247 [10]3 years ago
7 0

Answer:

Time in the air  t₁  =  7 s

Time in the sea t₂ =  5 s

Step-by-step explanation:

We will use the equation:   v =  d/t , where:

v is the average speed,

d the distance traveled, and

t time doing the trip

From v = d/t    ⇒  d = v*t

Therefore, if we call t₁ time in the air, and t₂ time in the sea, according to problem statement, we have:

t₁  +  t₂  = 12        (1)

16*t₁  +  3*t₂  = 127    (2)

A two equation system, from equation (1) we get

t₂  = 12 - t₁

And by substitution in equaton (2)

16*t₁  + 3 * ( 12 - t₁ ) = 127

16*t₁  + 36 - 3*t₁  = 127

13*t₁   = 91

t₁  = 91 /13

t₁ = 7 s

And    t₂  = 12 - 7

t₂ = 5 s

You might be interested in
Make 'm' the subject of the formula'k=3m-2
zaharov [31]

Answer:

m =  \frac{k + 2}{3}

Step-by-step explanation:

k = 3m - 2 \\ 3m = k + 2 \\ m =  \frac{k + 2}{3}

4 0
3 years ago
Read 2 more answers
Do one of the​ following, as appropriate.​ (a) Find the critical value z Subscript alpha divided by 2​, ​(b) find the critical v
aliya0001 [1]

Answer:

t=\pm 2.95

Step-by-step explanation:

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".  

The t distribution or Student’s t-distribution is a "probability distribution that is used to estimate population parameters when the sample size is small (n<30) or when the population variance is unknown".

The shape of the t distribution is determined by its degrees of freedom and when the degrees of freedom increase the t distirbution becomes a normal distribution approximately.  

Data given

Confidence =0.99 or 99%

\alpha=1-0.99=0.01 represent the significance level

n =16 represent the sample size

We don't know the population deviation \sigma

Solution for the problem

For this case since we don't know the population deviation and our sample size is <30 we can't use the normal distribution. We neeed to use on this case the t distribution, first we need to calculate the degrees of freedom given by:

df=n-1=16-1=15

We know that \alpha=0.01 so then \alpha/2=0.005 and we can find on the t distribution with 15 degrees of freedom a value that accumulates 0.005 of the area on the left tail. We can use the following excel code to find it:

"=T.INV(0.005;15)" and we got t_{\alpha/2}=-2.95 on this case since the distribution is symmetric we know that the other critical value is t_{\alpha/2}=2.95

8 0
3 years ago
Solve each equation.<br> 11. A number x divided by nine is two.
ivanzaharov [21]

Answer:

18 is the correct answer to this

Step-by-step explanation:

18/9=2

6 0
3 years ago
A point with coordinates (a, b) is plotted on a coordinated plane. The values of a and b can be any positive or negative integer
natali 33 [55]

Answer:

I think it's x-axis.

Step-by-step explanation:

but me could me wrong

3 0
3 years ago
The area of triangle ABC is 31 1/4 square centimeters. What is the measure of side b?
zhuklara [117]

Answer:

5/ sqrt2

Step-by-step explanation:

A=b.a.SinC

3 0
3 years ago
Other questions:
  • Find the zeros for y=x^2-3x-10
    8·2 answers
  • Factor Completely: 100x2 - 1
    14·1 answer
  • a box 750 grams. there are 25 such boxes. what is the total weight of the boxes in kilograms? give your answer to the nearest te
    14·1 answer
  • What is the area of a rectangle that measures 9cm by 81mm?
    7·1 answer
  • Devin has a change jar that contain only half dollars and pennies. He has 93 coins which add up to a total of $23.96. How many o
    5·2 answers
  • Help fast pls
    13·1 answer
  • In TUV the measure of V=90 TU=88 and UV=43 feet. Find the measure of T to the nearest tenth of a degree​
    5·2 answers
  • A grocery store owner asked the first 20 children who visited the store one day about their favorite snack. This is what type of
    15·1 answer
  • What is the slope of the line given by the equation below?
    14·1 answer
  • What is the mean median and mode of 201,201,200,199,199
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!