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.
Find the median first. The middle of all the numbers.
5, 7, 8, 10, 11, 13, 14, 18, 27
11 is the median.
Then find the median of the upper quartile.
The upper quartile consists of numbers...
5, 7, 8, 10
Since it is an even set of numbers add the two in the middle and divided by two. So 7 plus 8= 15/2.
7.5 is your upper quartile.
1. The answer would be (D). This is because you will plug is the (x) of the ordered pair into the equation(y=-2x), so first off would be (y=-2(-2)). since your multiplying a negative time a negative, you will get your (y) which is 4. Now you do this with the rest. -2(1)=-2 and -2(3)=-6.
2. This would be (A). This answer is simple. First you will take one of the equations (y=-x-1) and plug x into it's place so, y=-3-1, getting your answer(y) as being -4. Now you do the same with the other pair. y=-5-1, getting -6, showing (A) as your answer.
3.The answer will be (A)y is 2 times x. this is because you wou would make out the equation from the answer (y=2x). Now knowing your equation, all thats left is plugging in your (x) factors. so y=2(1), getting your (y) value of 2 and you would do this with the rest of your x factors.
4. y=5+x
y=5+(2)= 7
y=5+(3)= 8
y=5+(4)= 9
5. (B)y is 3 times x
y=3(x)
y=3(3)=9
y=3(4)=12
y=3(5)=15
6. (C)y is 6 less than x
y=6-(x)
y=6-(8)=2
y=6-(9)=3
y=6-(10)=4
No is twelve and forty-five ten thousandths
