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
Eddi Din [679]
3 years ago
8

H=255-21t-16t^2 PLEASE HELP!!

Mathematics
1 answer:
Colt1911 [192]3 years ago
4 0

Answer:

3.15 seconds is the answer.

<u>Explanation</u>

when the ball touches the ground, h =0

hence,

0=255-21t-16t²

16t²+21t-225=0

here a=16 ,b=21, c= -225

t=   \frac{ - b± \sqrt{ {b }^{2}  - 4ac} }{2a} \\  \\ t=   \frac{ - 21± \sqrt{ {21}^{2}  - 4 \times 16 \times  - 225} }{2 \times 16} \\  =  \frac{ - 21 ± \sqrt{441 - ( - 14400)} }{32} \\  =  \frac{ - 21± \sqrt{14841} }{32}  \\  =  \frac{ - 21±121.82}{32}  \\  \\ t =   \frac{ - 21 + 121.82}{32}  \: or \:  \: t =  \frac{ - 21 - 121.82}{32}  \\ t = 3.15 \:  \: or \:  \: t =  - 4.46

time cannot be negative, hence t = -4.46 can be avoided

The ball takes 3.15 seconds to hit the ground.

You might be interested in
Evaluate the expression when b=-6 and y=4.<br> b-6y
Harlamova29_29 [7]
-6 - 6(4)
-6 -24 = -30
So -30 is ur answer :)) hope I helped
7 0
3 years ago
Read 2 more answers
suppose for everyone cup of rice I add 2 3/4 cups of water. If I add 2 1/2 cups of rice, how much cups of water do I add?
Brrunno [24]

Answer:

6 7/8

Step-by-step explanation:

Since 1 cup of rice is added to 2 3/4 water

We are to determine the Amount of water to be to 2 1/2 cups of rice

Let the unknown number for water be x

So let's solve

1 cup of rice=11/4 water

5/2 cup of rice=x water

Cross multiply

x=5/2×11/4

x=55/8

X=6 7/8

Therefore,6 7/8 water is needed

8 0
3 years ago
Describe what the notation Upper P (Upper B vertical line Upper A )represents.
sergey [27]

Answer: Option 'D' is correct.

Step-by-step explanation:

Since we have given that

Upper P (Upper B vertical line Upper A)

means

P(B|A)

It means that probability of getting event B given that Event A is occurred.

D. The probability of event B​ occurring, given that event A has already occurred. is also expressed as P(B|A)

Hence, Option 'D' is correct.

4 0
3 years ago
Rearrange the formula C = 5/9 (F − 32) for F.
shtirl [24]
The answer is (9c/5)+32=F
5 0
3 years ago
Read 2 more answers
A, B and C are corners of a parallelogram
slamgirl [31]

Answer:

Step-by-step explanation:

in a parallelogram diagonals bisect each other.

so mid points are same.

Let coordinates of D be (x,y)

mid point of AC=midpoint Of BD

(-2+5)/2=(x+3)/2

x+3=-3

x=-3-3=-6

x=-6

(3-3)/2=(2+y)/2

y+2=0

y=-2

so D is (-6,-2)

5 0
3 years ago
Other questions:
  • If 168 chocolate chips weigh 5 1 4 ounces. How many chocolate chips are in an ounce?
    12·1 answer
  • What does a residual value of –4.5 mean in reference to the line of best fit? The data point is 4.5 units above the line of best
    10·2 answers
  • Ava wants to figure out the average speed she is driving. She starts checking her car’s clock at mile marker 0. It takes her 4 m
    11·2 answers
  • What is the greatest common factor of the terms in the polynomial 8x4 – 4x3 – 18x2?
    11·1 answer
  • Help me with number question 7
    6·1 answer
  • PLEASE HELP ALGEBRA 1
    15·1 answer
  • What is an outlier number?<br>​
    10·2 answers
  • The height of Figure A is doubled to create Figure B. How will the surface area be affected?
    14·2 answers
  • Please help ASAP
    11·1 answer
  • A fabric store is having a sale. Fleece fabric has an original price of $18 per yard. It is on sale for 30% off the original pri
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!