vi is going in the positive direction (up). (That's my choice). a (acceleration) is going in the minus direction (down). The directions could be reversed.
Givens
vi = 160 ft/s
vf = 0 (the rocket stops at the maximum height.)
a = - 9.81 m/s
t = ????
Remark
YOu have 4 parameters between the givens and what you want to solve. Only 1 equation will relate those 4. Always always list your givens with these problems so you can pick the right equation.
Equation
a = (vf - vi)/t
Solve
- 32 = (0 - 160)/t Multiply both sides by t
-32 * t = - 160 Divide by -32
t = - 160/-32
t = 5
You will also need to solve for the height to answer part B
t = 5
vi = 160 m/s
a = - 32
d = ???
d = vi*t + 1/2 a t^2
d = 160*5 + 1/2 * - 32 * 5^2
d = 800 - 400
d = 400 feet
Part B
You are at the maximum height. vi is 0 this time because you are starting to descend.
vi = 0
a = 32 m/s^2
d = 400 feet
t = ??
formula
d = vi*t + 1/2 a t^2
400 = 0 + 1/2 * 32 * t^2
400 = 16 * t^2
400/16 = t^2
t^2 = 25
t = 5 sec
The free fall takes the same amount of time to come down as it did to go up. Sort of an amazing result.
Hello there!
First, we need to admit that math is a hard subject. So, how do we handle hard stuff? We find an easy way. Right?
Well same goes here. They give the fractions to drive us crazy. Let's find the easiest way...
The easiest way is to turn them into decimals.
1 3/7 = 1.42 which is the amount of pages he reads
2/3 = 0.67 minute.
The are asking us how many pages does he reads per minute.
So we gonna say:
Charlie reads 1.42 pages ......> 0.67
Charlie reads x pages.............> 1minute
Cross multiply
0.67 * x = 1 * 1.42
0.67x = 1.42
x = 1.42/0.67
x = 2.11
So, Charlie reads 2.11 pages in 1 minute.
I hope this helps. Please let me know if you have questions about the answer.
Thanks!
Answer:
The values are
x = -25/9 = -2 7/9
y = 7/3 = 2 1/3
Step-by-step explanation:
3x + 2y = -13 --------eqn 1
3x + 4y = 1-------------eqn2
Using eqn 2 to get the value of y
3x + 4y = 1
4y = 1 - 3x
Dividing both sides by 4,to get y
4y/4 =( 1 -3x) / 4
y = (1 - 3x) / 4
Since we've gotten the value for y, substitute the value into eqn 1
3x + 2y = -13
3x + 2(3x - 1)/4 = -13
Opening the bracket
3x + (6x - 2)/4 = -13
LCM = 4
(12x + 6x - 2) / 4 = -13
18x - 2 / 4 = -13
Then we cross multiply
18x - 2 = -13 * 4
18x - 2 = - 52
18x = -52 + 2
18x = -50
Divide both sides by 18, to get the value of x
18x/18 = -50/18
x = -25/9
or x = -2 7/9
The value of x is now known, so let's go back to eqn 2
Substitute x = - 25/9
3x + 4y = 1
3(-25/9) + 4y = 1
Open the bracket
-75/9 + 4y = 1
Make y the subject of the formula
4y = 1 + 75/9
LCM = 9
4y = (9 + 75)/ 9
4y = 84/9
To get y, divide both sides by 4
4y/4 = 84/9 / 4/1
y =
Note : when division changes to multiplication, it always be in its reciprocal form
y = 84/9 / 1/4
y = 84 * 1 / 9 *4
y = 84/ 36
y = 7/3
Or
y = 2 1/3
Answer:
100 is correct answer
Step-by-step explanation:
when ever anything ² , it means that number is multiplied by itself.
in above we multiple 10 with 10 and we get 100.
hope it helped you:)
