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.
Answer:
D. "If the graph of two variables is not a linear function, then the two variables are not directly proportional"
Step-by-step explanation:
The contrapositive of a statement is basically you changing the conditional part of the statement with its result and then finding the negative of both. This is called Contraposition.
So, for the statement given:
"If two variables are directly proportional, then their graph is a linear function."
The contrapositive will be:
"If the graph of two variables is not a linear function, then the two variables are not directly proportional"
Multiply the variable k times 4 would give you 4k.
Then cross multiply 14x8 = 112
Therefore, you would have 4k = 112.
Divide 112 by 4 to get your answer!
Answer:
i think you got that right its negative
Step-by-step explanation:
