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
n200080 [17]
4 years ago
6

A rock was thrown from the top of a cliff such that its distance above sea level was given by s(t)= at² + bt + c, where t is the

time in seconds after the rock was released. After 1 second the rock was 63 m above sea level, after 2 seconds 72 m, and after 7 seconds 27m.
Mathematics
1 answer:
frutty [35]4 years ago
7 0

Answer:

<h2>a) a = -3, b = 18, c = 48; </h2><h2>s(t) = -3t²+18t+48</h2><h2>b) 48m</h2><h2>c) 8secs</h2>

Step-by-step explanation:

The question is incomplete. Here is the complete question.

'A rock was thrown from the top of a cliff such that its distance above sea level was given by s(t)=at²+bt+c, where t is the time in seconds after the rock was released. After 1 second the rock was 63 m above sea level, after 2 seconds 72 m, and after 7 seconds 27 m. a. Find a, b and c and hence an expression for s(t). b. Find the height of the cliff. c. Find the time taken for the rock to reach sea level.'

Given the equation of the distance modelled as s(t)=at²+bt+c

If after 1 second the rock was 63 m, then 63 = a+b+c

If after 2 seconds, the distance was 72 m then 72 = 4a+2b+c

Also if after 7 seconds, the distance is 27 m, then 27 = 49a+7b+c

i) Solving the 3 equations simultaneously to get a, b and c we have;

a+b+c = 63 ... 1

4a+2b+c = 72 ...2

49a+7b+c = 27 ...3

Subtracting 2 from 1 and 3 from 2 we will generate 2 new equations as shown;

eqn 2- eqn1: 3a + b = 9...4

eqn 3- eqn 2: 45a + 5b = -45

eqn 3- eqn 2: 9a+b = -9 ... 5

solving 4 and 5 simultaneously

3a + b = 9 ...4

9a+b = -9 ... 5  

Taking the difference of 4 and 5 we have

6a - -9-9

6a = -18

a = -3

substituting a = -3 into equation 4 to get b we have;

3(-3)+b = 9

-9 + b = 9

b = 9+9

b = 18

substituting a = -3 and b = 18 into equation 1 to get c we have;

-3+18+c = 63

15+c = 63

c = 48

a = -3, b= 18 and c = 48

The distance function will be s(t) = -3t²+18t+48

ii) If the height of the cliff is modelled by the equation  s(t)=at²+bt+c

The height of the cliff is at when t = 0

s(0) = -3(0)²+18(0)+48

s(0) = 48m

The height of the cliff is 48m

iii) At the sea level, the height of the rock will be 0m, substituting this into the modeled equation for the height to get the time we have;

s(t)=at²+bt+c

0 = -3t²+18t+48

3t²-18t-48 = 0

t² - 6t - 16 =0

t² - 8t+2t - 16 = 0

t(t-8)+2(t-8) = 0

(t+2)(t-8) = 0

t = -2 or 8

Taking the positive value of the time, t = 8secs

Time taken for the rock to reach sea level is 8secs

You might be interested in
Order from least to greatest. 10/8, 1.2, 0.556, 0.8%
Vsevolod [243]

The order from least to greatest is 0<u>.8%, 0.556, 1.2 and 10/8</u>

<h3>Ordering of numbers</h3>

In order to order the given numbers, we will first have to write them as a percentage as shown.

Given the number below

10/8, 1.2, 0.556, 0.8%

Convert to percentage

10/8 = 125%

1.2 = 120%

0.556 = 55.6%

0.8%

Hence the order from least to greatest is 0<u>.8%, 0.556, 1.2 and 10/8</u>

Learn more on ordering here; brainly.com/question/12399107

#SPJ1

8 0
2 years ago
12 more than (-17) is<br><br> A. 29 B. -29 C. -2 D. -5
Ivanshal [37]
-5 because 12+-17 is -5
7 0
4 years ago
Read 2 more answers
Answer if you want, 10 points
rjkz [21]

Answer:

hi

Step-by-step explanation:

for example

\frac{8}{4} = 2 \\  \\ 1 \times \frac{4}{5}  =  \frac{9}{5}

in the second one you should multiple 5 and 1 then add 4

8 0
3 years ago
HELPPPP DUE SOON!!! WILL MARK BRAINLYIST AND 10 POINTS
larisa86 [58]

Answer:

688.7

Step-by-step explanation:

Top and Bottom

Area = 3/4 * pi * r^2

r = 6

Area = 3/4 * 3.14 * 6^2

Area =                                                               84.78

Don't round yet.

Vertical surface

Vertical surface = 3/4 * pi * d * h

d = 12 inches (the diameter)

Vertical surface = 3/4 * 3.14 * 12 * 15

Vertical surface =                                          423.9

Two inner faces

They are both rectangles

Area = 2 * L * W

L = 15

w=6

Area = 2 * 15 * 6                           <u>                  180</u>

Total                                                               688.68

Total = 688.7

7 0
3 years ago
Consider the transpose of Your matrix A, that is, the matrix whose first column is the first row of A, the second column is the
Zarrin [17]

Answer:The system could have no solution or n number of solution where n is the number of unknown in the n linear equations.

Step-by-step explanation:

To determine if solution exist or not, you test the equation for consistency.

A system is said to be consistent if the rank of a matrix (say B ) is equal to the rank of the matrix formed by adding the constant terms(in this case the zeros) as a third column to the matrix B.

Consider the following scenarios:

(1) For example:Given the matrix A=\left[\begin{array}{ccc}1&2\\3&4\end{array}\right], to transpose A, exchange rows with columns i.e take first column as first row and second column as second row as follows:

Let A transpose be B.

∵B=\left[\begin{array}{ccc}1&3\\2&4\end{array}\right]

the system Bx=0 can be represented in matrix form as:

\left[\begin{array}{ccc}1&3\\2&4\end{array}\right]\left[\begin{array}{ccc}x_{1} \\x_{2} \end{array}\right]=\left[\begin{array}{ccc}0\\0\end{array}\right] ................................eq(1)

Now, to determine the rank of B, we work the determinant of the maximum sub-square matrix of B. In this case, B is a 2 x 2 matrix, therefore, the maximum sub-square matrix of B is itself B. Hence,

|B|=(1*4)-(3*2)= 4-6 = -2 i.e, B is a non-singular matrix with rank of order (-2).

Again, adding the constant terms of equation 1(in this case zeros) as a third column to B, we have B_{0}:      

B_{0}=\left[\begin{array}{ccc}1&3&0\\4&2&0\end{array}\right]. The rank of B_{0} can be found by using the second column and third column pair as follows:

|B_{0}|=(3*0)-(0*2)=0 i.e, B_{0} is a singular matrix with rank of order 1.

Note: a matrix is singular if its determinant is = 0 and non-singular if it is \neq0.

Comparing the rank of both B and B_{0}, it is obvious that

Rank of B\neqRank of B_{0} since (-2)<1.

Therefore, we can conclude that equation(1) is <em>inconsistent and thus has no solution.     </em>

(2) If B=\left[\begin{array}{ccc}-4&5\\-8&10&\end{array}\right] is the transpose of matrix A=\left[\begin{array}{ccc}-4&-8\\5&10\end{array}\right], then

Then the equation Bx=0 is represented as:

\left[\begin{array}{ccc}-4&5\\-8&10&\end{array}\right]\left[\begin{array}{ccc}x_{1} \\x_{2} \end{array}\right]=\left[\begin{array}{ccc}0\\0\end{array}\right]..................................eq(2)

|B|= (-4*10)-(5*(-8))= -40+40 = 0  i.e B has a rank of order 1.

B_{0}=\left[\begin{array}{ccc}-4&5&0\\-8&10&0\end{array}\right],

|B_{0}|=(5*0)-(0*10)=0-0=0   i.e B_{0} has a rank of order 1.

we can therefor conclude that since

rank B=rank B_{0}=1,  equation(2) is <em>consistent</em> and has 2 solutions for the 2 unknown (X_{1} and X_{2}).

<u>Summary:</u>

  • Given an equation Bx=0, transform the set of linear equations into matrix form as shown in equations(1 and 2).
  • Determine the rank of both the coefficients matrix B and B_{0} which is formed by adding a column with the constant elements of the equation to the coefficient matrix.
  • If the rank of both matrix is same, then the equation is consistent and there exists n number of solutions(n is based on the number of unknown) but if they are not equal, then the equation is not consistent and there is no number of solution.
5 0
3 years ago
Other questions:
  • Solve system by graphing 2x-6y=12 x+y=2
    15·1 answer
  • I forgot how to do this!! i'd like help please!!
    8·1 answer
  • sharon arrange flowers in 5 jars for a party. she puts 4 carnations, 4 roses,and 2 daisies in each jar.how many flowers does sha
    7·1 answer
  • Write Which congruence theorem is used and also write a congruency statement
    7·2 answers
  • What is 55/99 Rounded to the nearest half
    15·2 answers
  • The distribution of the amount of money spent by first-time gamblers at a major casino in Las Vegas is approximately normal in s
    11·1 answer
  • 14. How many degrees does the minute hand of the clock go through between 6:47 and 11:18?
    13·1 answer
  • Each cement block weighs 0.6 kilograms. How much do 10 blocks weigh in total?
    8·2 answers
  • Explain why a step in solving the equation 4n= -36 is to divide both sides by 4. Then solve the equation
    12·1 answer
  • Question is download
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!